A week ago I wrote about Civilization V being released last week.
Well, I played the game, and it sucks. Incredibly boring. I never got past the ridiculously unresponsive gameplay (it takes the computer far too long to think about each move) and the annoyingly cluttered interface where you have to keep clicking messages. People who've played the game longer have complained about the really bad AI and the the lack of complex strategies which made Civ 4 so enjoyable.
I highly recommend Civ 4 over Civ 5, and the fact that Amazon.com is selling a version of Civ 4 complete with the Beyond the Sword (BTS) expansion for only $10.49, that’s a huge bargain compared to $50 for Civ 5.
If you take my advice on Civ 4, you also need install the BTS 3.19 patch and the Better BTS AI mod to make the game perfect. (There’s a forum discussing the Better BTS AI project.) My advice is also to play with "Small" maps because the Standard and larger maps make the game take too long, and to play with technology trading turned off (which you can get to in the custom game options menu) because technology trading adds too much diplomatic micromanagement to the game and forces you to game the AI in order to survive (if you don't participate in the technology-trading game, the AI civs will trade with each other and leave you in the dust).