Age of Mythology. Don't have it? Then go buy it. $35 bucks at Circuit City right now. Incredible game. Loads of fun, graphics are gorgeous, etc. If you have played any of the Age of Empires series then you'll get the hang of this game instantly. And it's a whole lot more fun.

I'm in the Greek campaign right now...so far my favorite Myth units are a huge pack of Bull Minotaurs. Boy are they fun! :)