I know the general consensus from old-school Civilization players is that this is a bit of a step backwards from Civ IV, but I couldn't disagree more. The interface is worlds more intuitive and I was happy to see they removed the ability to stack units which really just made battles harder to manage and judge. One conceit I'll have to make is the music, which doesn't hold a candle to Civ IV's.
Have you ever woken up in the morning and decided that you want to do absolutely nothing all day and yet be dreadfully enthralled? Just start a game of Civ 5 on the quickest settings! 12 hours later when America, China and inexplicably the Aztecs have finally teamed up against you just to murder you in cold blood you can count your day as mildly successful. Oh also its pretty fun.
I like this chapter in the Civ series because I was finally able to figure out the game and develop a winning strategy without (much) help from civfanatics.com. I still get "one more turn" syndrome while playing.
Latest update to an amazing turn based strategy game. One unit per tile on hexes adds strategy and actually makes it less tedious at the same time. The city states are also a really fun addition. Cons: Initial release was very buggy and still has problems over a month later. But they are fixing a lot of the issues. Many of the changes take getting used to and some say it feels slower than Civ4.
(will update once I play more) - love the new hex-based combat. Much more thought required. Awesome modding tools for custom game play options. Cons: Culture and religion are of less importance compared to IV. This could bug me, but we'll see. This game will test the limits of my gf's love for me.