I was thinking of attempting something like this myself. Much easier to just throw some thoughts out there & let you (or someone else) put it all together, tho.
One thing that I'd thought of while dreaming up the post is that the relative values of the wonders in Civ4 vary drastically depending on one's playing style or the type of victory the player is going for in that game. There just aren't any "must have" wonders in this game, like in previous versions of Civ--you can still win if you whiff on any of them. Anyway, I'll just throw out a few that I do consider to be fairly important:
Stonehenge - If you don't have the creative trait, building Stonehenge can be a big boost during the critical land-grabbing portion of the early game. The automatic 1 culture point (cp) that you get in each new city allows for a great deal of flexibility--you can confidently plop your settlers down 2 squares away from several resources, knowing that around the time you've built you first military unit in that city, it'll be growing to cover those tiles. The automatic culture boost also makes it easier to grab key choke points on the map. And, of course, this gets you going towards your first great prophet, who you'll need to build that holy shrine. Incidentally, I've also found that building Stonehenge in your capital after sending out your first settler gives that city some time to grow unimpeded, which will make it easier to build more settlers later (or to build up a army to take out your closest neighbor).
The Oracle - Getting that free tech can make the difference in your first war, even if that war hasn't started yet (I generally try to get Metal Casting as my bonus tech, allowing me to build the forges I need to really crank out my swordsmen, axemen, and the like). If you manage to build it in the same city as Stonehenge, hey--even more great prophet points!
The Parthenon - If you haven't figured it out yet, great people are a key component to beating Civ4. And getting a 50% boost to
all your cities' great person production definitely doesn't hurt in that regard. On the downside, this wonder is very expensive (400 hammers), and especially if you've got the Romans or Aztecs next door, you probably have other things to use those hammers on.
The Great Library - Two free science specialists in every city--that will help to get you an early tech lead (or to stay close to the AI civs on more difficult levels). When you combine this wonder with the representation civic, that's a helluva lot of research for "free".
Versailles - Gives you a second forbidden palace, which cuts down a great deal on your maintenance costs (and therefore keeps your economy running well enough to power your research). I've also found that the AI is notoriously slow about building this wonder, which helps your cause in closer games.
The Pentagon - If you're going to be fighting a modern era war (and let's face it--you probably will be), then getting 2 free experience points for every unit built in every city will be a huge boost. Combine this wonder with the aggressive trait, a barracks, and the vassalage/theocracy civics, and every ground unit you produce will start with three promotions (plus your automatic combat 1 promotion).
The Three Gorges Dam - Powers up all the factories in all your cities on that continent, which makes this a
huge timesaver in a pangea game (or just for a civ that started on a large continent). And since it gives the benefits of a hydro dam to every city, you don't have to worry about the added polution that comes from coal plants (or the chances of a meltdown that come with nuclear plants). A factory/power plant is a must for building any of the modern era military units, as well as space ship parts.
All of the national wonders are worth building at one point or another (with the possible exception of The Globe Theater), and with proper planning, can create some pretty awesome cities.
There aren't really any wonders that I think are a total waste of time, although The Spiral Minaret is pretty useless if you plan on spending most of the game under the Free Religion civic. The "don't build city walls" adage from earlier Civ games (if you're defending in your cities, you're already screwed) could also apply to The Chichen Itza.
As far as projects go, I still haven't figured out the point of The Internet in this game--by the time you can build it, I can't imagine that there are too many techs you don't already know.
That's my take on it, anyway. Feel free to use whatever you wish & ignore the rest.
