Civilization IV is my current game. I’ve owned all four versions and it is probably the best. I didn’t care for Civ3 much. Duke Nukem is probably my all time favorite. The last version of Castle Wolfenstein was pretty good.
I think it's just astonishingly good. Of course, I also see why people like IV, my son has been hinting about it for months. Civilization Revolution is definitely promising...will let you know when I get a chance to play it some more.