Which is better for co-op games: 360 or PS3?

*promptly changes his XBL gamertag to DanieLoony*

Just buy your console for single player games you like.

If you have 2 PC's already, just get a lan line and play those games. There is a much larger archive of multiplayer games playable over PC. And if its a 360 title released by Microsoft like Halo, Gears of War, and Army of Two, it's going to PC anyway.

Every system has Call of Duty 4 I believe.