I'm going to have to disagree with the author of this thread on the whole 'Temples and Cathedrals are not Necessary' idea. From reading through the posts, I've gathered that these comments are based on experiences playing on Huge Pangea maps on Regent difficulty. With no offense intended, these conditions are hardly typical of all games of Civ3 being played.
To be honest, this strategy is just going to fall flat on its face on Emperor/Deity. You CANNOT get through the game without ever building the happiness city improvements. Remember, you only get 1 content citizen at these levels; you need military police or a temple just to stay content at size 2! Whether you like it or not, each city IS going to need a temple just to avoid running a high luxury tax all the time.
The luxuries + marketplaces strategy is a good one, but what if you don't start next to 3-4 luxuries? It sounds like some of those commenting here are simply creating a new game when they don't have that kind of starting location; I hope I'm just misinterpreting the posts. On Deity especially, you cannot simply attack and kill everyone to get 8 luxuries. With luck you can trade for luxuries, but they are still going to be very expensive. When your cities hit size 10-12, they are definitely going to be needing cathedrals as well.
And Scientific as the best civ trait? I very strongly believe it's the WORST civ trait! Libraries may be 1/2 cost, but you shouldn't be doing any research yourself on Emperor/Deity as it is! Religious is indeed overvalued, but Industrious is, if anything, underrated as a strength. Double speed workers is amazingly powerful when used in the right hands.
I really don't think the Pyramids are better than the Industrious trait either. Granted, this comment was made with the understanding of playing on a Huge Pangea map, but it's still not true. The Pyramids provide a huge benefit, true, but I would still rather put those shields into initial expansion rather than tying one of my top cities down to a wonder for 30-40 turns early in the game. And then there's the problem of getting the wonder at all; in my recent Deity game the Pyramids were built in 1910BC. Care to try to win that wonder race?
Well, I'm not trying to be insulting to anyone here, but my experiences playing on all different map sizes and landforms have found that this strategy will not be effective in Emperor/Deity games. The point that temples are not necessary if you have marketplaces and control all 8 luxuries is a good one, but unfortunately any game in which this occurs will probably be already decided. I would encourage others out there to try their hand at a Deity game and see if you can get by without building any temples - I doubt it!