Ah, so we're discussing the best wonders in the worst wonders thread, heh heh. Lots of interesting points have been made here, so let me add some of mine.
Well, first off, the worst wonder, hands down imho, is the Great Library, since it actively hurts my gameplay like no other wonder can or does.
The top must have wonders are Michelangelo's Chapel and Bachs Cathedral with little to choose between 'em. I must have both. I'll usually give up if I can't attain them, they are so dear to me.
The best of the ancient wonders is a hard one. You'd think it would be Hanging Gardens since I love MC and BC so much, but as I consider pottery to be a low priority tech it isn't. Which leaves Marco Polo's Embassy and Pyramids, which I both consider to be highly desirable get 'em if you can wonders.
I never used to mind having Oracle, since the first city improvement I made was always a temple. However, a change in my playing style is starting to make this obsolete.
Colossus and Lighthouse are iffy. Lighthouse is only a contender if you are engaged in an early sea campaign, and Colossus is only a contender if you think you're far enough ahead to get a Super Science City going, which requires a considerable amount of planning ahead with no certainty that you'll make it. I consider achieving a well planned SSC to be a game winner, so if I think I'll be able to get one going, Colossus becomes as close to being as desirable as MC and BC as it gets.
For me it all depends on the context of the game, you see...and thinking about it sets my head spinning...yet you guys have lots of interesting ideas and opinions for me to think about as well. Thanks for your contributions, I really enjoy reading them.