All the games mentioned are great. Army of two the original and sequal have great action even if the stories really suck. I would buy borderlands though it is the longest coop game I have ever played, and the downloadable content is great it really changes the experience and adds many hours to an already great time with a friend.
I know you don't want downloadable games, but screw it these games are great coop games: Castlecrashers, Trine and Laura Croft and the gaurdian of light. These are all $15 or less.








