Here is the list of results to date, complete with my personal summary of why the Wonder placed where it did, based on collating all the various opinions provided with the up-votes and down-votes:
E - Tier Wonders
37. Estádio do Maracanã - I am convinced this only reached number 37 because it is such a forgettable Wonder everyone forgot up to this point. Mea culpa, I was also one of those people! It is certainly in my view a lot worse than many of those below it on this list, and really sneaked out of F tier. It gives +6 to Culture and +2 to Amenities to every City a Civ has. Here's the big problem - it's an Atomic Era Wonder. Even if you're pursuing a Cultural Victory, you have now switched over to Tourism - Culture is becoming increasingly useless at this point in the game, partly because there's very few useful Civics left (Social Media, the final government types), and partly because you probably already have a fantastic Cultural economy if you've got this far and would otherwise consider building the Estadio. The Amenities can give a reasonable boost, but like... late-game Amenities are very rarely a problem. Also, this is completely on the wrong side of the Civics tree - most people will be gunning for Environmentalism at this point.
When to build this?: I guess if you have a really big Amenity problem and have a lot of other problems preventing you accessing other Amenity solutions?
38. Colossus - A very mediocre Wonder. It gives you +3 Gold, +1 Great Admiral Points, +1 Trade Route Capacity, and a free Trader, all for 400 Production. Now suppose you build one Harbour, one Lighthouse, and one Trader. As long as your Harbour had at least one adjacency bonus, you've got the same amount of Gold base, the same amount of trade route capacity, the same amount of traders, twice as many Great Admiral Points, and a whole host of additional bonuses (food from the Lighthouse etc)... and it probably all cost less Production. The Colossus is like being able to build a second Lighthouse in a City for a huge Production mark-up. The law of diminishing returns tells you why this is a very low priority.
When to build this?: Having said all the above... I actually probably build this Wonder in almost all games eventually. Why? Because the AI barely ever goes for it, as far as I can work out, and a free Trade Route is a free Trade Route. Often I'm building this late into the Industrial era just because it's there and I have a City spinning a wheels for a bit. So I guess: build it whenever you have a City that meets the Build Conditions, there aren't really any opportunities to get an extra Trade Route any other way, and a Trade Route would be quite useful (which is often, to be fair). While this Wonder is very low value, the fact it isn't competed for and the fact it still has some value that assists all Victory Conditions mean that it doesn't languish further below.
39. Angkor Wat - Angkor Wat gives you +1 Population and +1 Housing in all Cities, and +2 Faith in the City it is built. It is... okay. The trouble is: suppose you have 10 Cities when you build this, and as a result you hit 10 extra Population. Suppose each of those works a +3 Production tile, for an extra +30 Production a turn. It'd still take 24 turns just to break even on the Production cost for this Wonder, set across all Cities. In addition, distributed Production is usually worse than concentrated Production - being able to finish things in one city is very useful. Consequently, the return on investment here is very slow - you're spending a lot of one resource to get lots of that resource back after time. In addition, it can lead to a sudden shock of Amenity problems if you were already managing Pop on the very edge of your Amenities (which is normally a good idea, why would you be wasting the slack prior to this point?).
When to build this?: When you have spare Amenities (perhaps because you were cramped in and so can't settle, but haven't yet fully grown your Cities because you're housing limited), and you don't have any other immediate Production demands (an army, better Wonders, Builders). To be fair, the AI doesn't like this one much either, so you can pick it up quite late and not be challenged on it much. However, the period you'll access Angkor Wat has a bunch of good generalist Wonders - Forbidden Palace, Kilwa Kisiwani, Potala Palace, etc. - coming online, and Angkor Wat is pretty low by comparison.
40. Jebel Barkal - This awards 6 Iron per turn and +4 Faith to every City within 6 tiles. I think this Wonder was perhaps a little underranked, because people seem to see the +6 Iron as the major feature - perhaps because this Wonder unlocks with Iron-Working. However, that's just a side show - although it can be nice if you have no other access to Iron, or want a little money-turner for the AI. No, the real power here is the +4 Faith to every City within 6 tiles. A reasonably good placement of the Jebel Barkal should still be generating about 28-32 Faith, for 7 to 8 Cities within range. This is... a lot of Faith, and very early too. Compare to our discussion of the Kotoku-In earlier. 28 Faith is the same Faith as 7 Temples. Wowzers! If you need a *lot* of Faith early on... this is your Wonder. And there's lots of reasons you'd want this very early Faith, for every Victory Condition - Jebel Barkal is available early enough to still be in the Monumentality period of the game, when you can Golden Age into Faith Buying Settlers and Builders. Jebel Barkal can drive a big expansion in your Empire.
The drawback? There's two. First is just this has very specific placement requirements - Desert Hills - and Desert tiles are baaaad areas to be in the early-game. You don't want to be settling Cities near them in the early-game. However... Jebel Barkal needs quite dense city placement to have much effect. The combination of needing Desert to place and needing dense city placement to be powerful means that Jebel Barkal is very niche - there's not too many games where it will be great from the moment you can get it. The second is that the AI will gun for this quite heavily if they do have Desert Hills, so you can't just leave it for later in my experience. However, if you do end up with a stray Desert Hill near a City, and it doesn't make the surrounding area bad to settle densely, then Jebel Barkal should absolutely be considered.
When do I build this?: You should build Jebel Barkal if you are capable of settling Cities densely around the City which will contain Jebel Barkal (without making those cities rubbish), and you need a big injection of early Faith, either to fuel a Monumentality Settler rush, or to begin a Religious Victory.
41. Hanging Gardens - +2 Housing in the City that builds it; +15% growth. The trouble with the Hanging Gardens is that growth in the early-game is very much hard-capped by Housing, and there aren't really a huge number of Housing options very early on. Food is... not really so relevant after the initial few POPs. So Hanging Gardens gets you to a point everyone else was going to reach slightly faster, but then you're all stuck at the same point anyway. Obviously, if you hit your 5th POP 15% faster than someone else does, you get that that much time's worth of extra yields, but growth early on is pretty fast anyway, and this feels quite marginal. The only place this impact is really powerfully felt is in the city that builds it, but that's an awful lot of Production cost for very little gain. It's hard to imagine how you'd want to build this in the early game, when usually there are the highest number of competing priorities as your Civ hasn't begun to specialise so heavily yet.
When to build this?: Well, my personal opinion is the Hanging Gardens should have gone sooner so I could put it in the F tier, because my answer is generally going to be "never". It's very difficult for me to see a situation where this is your best use of Production. You'll get more extra POPs by founding a City, so you have to have no expansion room, and you need a lot of excess housing, which is very unusual unless you are a Civ which has bonuses to Housing. Maybe you can get some mileage out of this as the Maya, but I'm skeptical.
42. Hermitage - the Hermitage offers +4 Work of Art slots, and +3 Great Artist Points per turn. This would be okay... except the Hermitage is ludicrously expensive for this. 1450 production?!? It would often cost less to produce two Settlers, build two Theatre Squares, and build two Amphipheatres, for the same impact on Work of Art Slots and Great Artist Points except now you have two extra Cities too.
Also, you have much better uses for your production. If you're considering building the Hermitage, you're going for Cultural Victory. If you're going for Cultural Victory, you enter the Industrial Era in the Civics tree via Opera & Ballet the vast majority of the time, because Art (doesn't cost Production, just happens naturally over time or with a supplement of Faith or Gold) is normally a quicker way to CV than Archaeology (costs a lot of Production). That means you'll usually miss the Hermitage to an AI. But if you take the top side of the Civics tree in a CV, that means you're banking on Archaeology rather than Art. But if you're banking on Archaeology, you normally have very high Production costs to go towards Archaeologists (I suppose again unless you're Ethiopia...). So you can't be building this.
When to build this?: Honestly, I think this is worse than the Kotoku-In and probably should have been in F-tier. The best I can say about it is that you can build it in a Cultural Victory when you have no other more useful Production demands (which is unlikely as there are lots of good Cultural Wonders shortly after like the Cristo Redentor and the Eiffel Tower, not to mention lots of builders to get National Parks and Appeal up to scratch, and a military to secure yourself in a period when Science is shooting along and the top-of-the-line unit can change quite quickly).
43. Kotoku-In - The Kotoku-In offers +20% Faith in the city in which it is built, and 4 Warrior Monks. The main problem the Kotoku-In has is that Warrior Monks are really terrible units that needed to be babied unendingly to get good. The promotion tree for Warrior Monks can make them impressive, but it takes so long they can't contribute to either Domination or Militarily-focused Religious Victory properly, and if you're going for other Victory conditions you're probably not building Kotoku-In. +20% Faith in the city in which the Kotoku-In is built isn't great either. There aren't too many sources of Faith in the game other than Holy Sites for most Civs, excusing those with unique aspects for Faith such as Ethiopia and the like. If you have a strong natural +4 Holy Site, +2 from the Shrine, and +4 from a Temple, then the Kotoku-In is adding... +2 Faith. Ouch. Even with Simultaneum, you get up to +4. That's half the amount the Simultaneum Temple is adding, it's nearly trivial.
However... once you've reached Reformed Church and Cartography, you have basically every tool you'd really need for Religious Victory, and more importantly, once you've finished Temples in all your Cities (unlocked at Theocracy), you don't really have as many pressing needs for Production as other Victory Conditions - after all, your main units are produced with Faith, not Production now. As Kotoku-In sits between Theocracy and Reformed Church at Divine Right, I often end up building this in an RV not because it is amazing but because I don't have any more pressing priorities. Consequently, this is the first Wonder I think sneaks into E-tier.
When do I build this?: You're going for a Religious Victory, and you have a City which has finished all the major Religious Infrastructure it needs at that point in the game, and you are reasonably militarily secure and don't need to produce any units. I wouldn't chop for it or be disappointed if it is missed, but RV has a bit of spare Production at this point in the game and Kotoku-In can be worth a flutter.
F - Tier Wonders
44. Great Bath - The Great Bath offers +3 Housing, +1 Amenity, immunity to floods in return for reduced yields from floods, and Faith on tiles after floods. This is... okay. The +3 Housing and +1 Amenity is probably the best part of this - the +1 Amenity pays for 4 extra pops, so the extra Housing comes without Amenity pressures early on and is equivalent to a free District. The trouble is, early on you can usually just... build a Settler and settle to an Amenity instead. Then not only do you get the same basic effect but also extra territory, force projection, build queue, etc. The Great Bath is available so early it has to compete with Settlers for Production and it just doesn't win that competition. In addition - the yields from Natural Disasters are really strong. Strong enough that putting up with them in exchange for the boosted yields is often better than shutting them down, particularly early on because of the cumulative effect. Being flooded is... pretty beneficial! You're throwing that away for a chance at Faith, but that chance is inconsistent and may not pay off any time soon. If you want Faith, you'll probably prefer reliable Faith. As the crowning cherry, the AI loves this and rushes it with the ferocity of a thousand suns. Most times you start this, you're just going to lose all your production.
When do I build this?: Again, very tempting to say "never". You need to be a) so cramped you have no room for expansion or building a Settler, b) on a floodplain, c) not capable of expanding militarily (then the Production is better spent on units), d) not really aiming for Faith directly (it isn't consistent enough, you'd aim for other Wonders), but looking to get at least some Faith and growth... I guess maybe if you're deciding early you want a Cultural Victory because you're very cramped, and all your neighbours are runaways that nevertheless have decided to spare you and you're trying a sneaky Culture win. This is't going to happen often, particularly because you have to commit to the Great Bath so early that you probably lack the information to really make this call.
45. Great Lighthouse - The Great Lighthouse's big selling point is giving +1 movement to naval units. The problem is naval units already tend to have pretty good movement, making the addition a marginal return; there's no terrain at sea to slow naval units; the AI is often pretty rubbish at maintaining a navy anyway so it's not like you need the +1 movement to overcome problems; and, the big problem that as we'll see above applies to a lot of military Wonders: rather than building the Great Lighthouse, you could have just built an extra two and a half Quadriremes. 2 extra Quadriremes, appropriately upgraded over time, will just make a lot more difference to your naval projection power than a smaller navy with slightly better movement.
When do I build this?: I am once again tempted to say never. In Archipelago maps or Fractal Maps which have ended up being extremely naval-oriented, this can sometimes aid with exploration and the like somewhat, helping lock down strategic locations. It's rare you'll make that judgment call. In some fairness to the Great Lighthouse, it isn't popular to the AI and can be picked up quite late if you fancy it for whatever reason.
46. Meenakshi Temple - The Meenakshi Temple suffers from Gurus being nearly useless. Even using the old Apostle Turtle - 6 Apostles clustered around a Guru, marching through initiating religious combat to get conversions - you only need 1 Guru per 6 Apostles. In reality, you'll have multiple fronts and can often retreat Apostles to be healed anyway. I play and win most of my Religious Victory games without ever using a single Guru. The Meenakshi does effectively turn Gurus into "Great Generals" for Religious Units, which is somewhat useful, but the AI is very bad at co-ordinating Religious Units anyway and you can usually beat them just by using the advantage of 2 Apostles against 1, rather than needing a support unit. That means you're usually better putting Production towards new Settlers or Holy Sites to support your Faith economy.
When do I build this?: I'm tempted to say "never", at least in single-player. Conceivably this might be somewhat useful if a Civ with stronger Religious units (e.g. Mongolia) suddenly starts a massive Religious snowball and becomes a real obstacle to your own Religious Victory. This is obviously quite niche.
47. Golden Gate Bridge - Again, the Golden Gate Bridge suffers from being extremely niche. The real power to this Wonder is not real allowing units to cross as though it was land (although all considerations of power aside, this is really fun and cool). That saves military units maybe 2 turns of movement at best from embarking and disembarking; it is rarely a life-saver or even that militarily useful. No, the real benefit is the huge boost to National Park Tourism in the city you build it in. However... because the Golden Gate Bridge needs to be placed over water, which for some reason National Parks can't include even if the water is lakes or coastal, a City which builds the Golden Gate Bridge often doesn't have that much room for National Parks anyway. It's very hard to get any mileage here.
When do I build this?: If you spot a great location for National Parks (lots of Mountains, essentially) where you think you can get at least 3 National Parks around the City you place, you might consider building this. It has particular synergy with Bull Moose Roosevelt, who might consider it slightly more often. It will be quite rare for these conditions to align, however.
48. Panama Canal - The Panama Canal's problem is just how niche it is. In many maps, the ability to connect two blocks of water 3 tiles away is, at best, a mild time-saver rather than a matter of crucial strategic importance. When you do find a site, it's often still not possible because oddly the Panama Canal cannot be built on hills despite this being a prominent feature of the Panama Canal in real life. Moreover, even when early in the game you do identify the rare occasion where you can see a Panama Canal site that might be useful, it then requires not placing any districts there even if it would be useful, only for your plans to be often ruined anyway by the late reveal of Nitre or Coal, meaning you just forced bad placement on yourself for nothing. The +10GPT is broadly forgettable by the stage in the game it comes. Finally, it's pretty popular with the AI as well, who love building it in weird and wonderful (read: useless) places.
When do I build this?: Potentially when you need more Gold per Turn and the map works out in just the right way such that your trade routes would go where you plan to build the Panama Canal Site; but to be honest you'll usually be better just spamming projects anyway. Honestly, this Wonder is basically built just for cool points, it will almost never make a positive contribution to victory.
49. Stonehenge - Stonehenge's main problem is that getting a Religion is really only half the fight. Once you have a Religion, you then need to spread it, which will require Missionaries. If you got your Religion from a Holy Site and Shrine combination, you get Missionaries. If you got your Religion from Stonehenge... you can't get Missionaries, unless you get a Holy Site and Shrine anyway. Perhaps Stonehenge could still be justified if it was easy to build and much faster than a Holy Site and Shrine at getting a Religion, but Stonehenge is very popular with the AI, and in any event it isn't really any faster than going Holy Site -> Shrine -> Holy Site prayers. That means most of the time, you're just wasting Production and setting yourself back. Not only is this Wonder not very useful, it is actively detrimental much of the time.
When do I build this?: Stonehenge is only to be built if it is absolutely essential you get the first religion, because a particular belief is critical to your entire strategy, but it doesn't matter too much if you are then slow to get Religious Infrastructure up from that point. The AI's favoured two options are Feed the World (not that good), and Choral Music (extremely good), so this is basically: build Stonehenge if you absolutely critically need Choral Music, presumably as part of a Cultural Victory. This is very niche and I can't see why you'd be making this decision. It will be very rare you build this Wonder.