Gears if you want a good, if short, single player and a pretty damn fun MP setup. Fallout 3 if you never want to see the light of day again cause of one helluva SP game. I voted for F3 if only cause it lasts longer.
I'm gonna go out on a limb and say Cod:WaW if you like to do the multiplayer.... The single player part of the game can be lacking but you can co-op online with friends to make it more interesting! Add the multiplayer that really never ends because of 65 levels and the ability to go presitge 10 times makes for a lot of…
I'd say Gears 2, and Left 4 Dead. I usually find that Multiplayer type games have a huge spike in player at launch, and everyone is of similar skill level. Then after a few months you'll be playing against the crazy Ubar-L337 who are rolling/turning/jumping while executing a perfect headshot 99% of the time, and have all…