I would recommend CoD3, because its a classic war game, with pretty good multi-player and is best as a general game of WWII. Left4Dead is an absolute must, especially with Live, and also getting the new CoD:MW2. I like GTA IV quite a bit, but I've never had the chance to play SR 1 or 2.
PC FTW
Battlefield: Bad CompanyLeft 4 Dead
Get: A game you like.Turok is fun. (Very challanging too.)
The new Turok was horrible.