What computer games do you like ?

I'm really into the Assassin's Creed series. I haven't picked up Assassin's Creed III, though. I have to either buy a new computer to play it, or rebuild the one I have. Who knows, maybe I'll just break down and get an Xbox. I haven't had a "new" gaming console since the N64, and I sold it not too long after I got it.

For those of you longing for the "old days" you can play classic Pong here:
http://www.jarkey.net/goplay/classic_pong_game.htm