Just bought two games in the last few months:

Redhead redemption on the 360. Interesting game. Love the way you can cheat at poker and end up in a gun fight, but
ultimately it feels a little souless. Plus the multiplayer actually removes half of the single player content! Apparently they're gonna add it back as a dlc. Cheeky fuckers.

Left 4 dead 2. I still haven't played the single player. You don't need to as to multiplayer is so amazing. Most online games encourage players to go off ok their own, but l4d2 actually punishes u if u don't act as a team becuz u all just get surrounded and die if u don't. This also makes you want to heal other, worse damaged players rather than yourself first. Prob one of the best multiplayer fps I've played so far...