I cannot even estimate how many hours of my life this game has consumed.  I fully blame my less than stellar grades in chemistry and physics on this game.  It sucks you in and won't let go.  I'm happy to say I've been Civ-free for about 4 months now, but I must admit just writing this review is firing up my cravings.  Oh man, maybe I'll play as the Japanese on Deity difficulty.  I don't believe I've ever beat it on that level.  So hard, the computer civilizations just spread like viruses!  Ok, I gotta go before this gets out of hand.  Suffice to say, this game is absolutely incredible, and it never grows old.  I also highly reccommed playing the expansion to this, which involves the Midgard scenario.  Good luck!