Best Co-Op Games?

What are the best Coop games you have played for PS2/PS3 ??

So far I ahve played through resistace:fom w/ my friend and im looking for more coop games.

You're not gonna get many replies on the PS3 front - I'm guessing that you're the only one on the forums who has a PS3. Others who bought one sold it a few days later.

Profit, or is it that bad? Because I like it.

MK: SM was pretty cool, thats the only one I've played on PS2 that is co-op and didn't suck, like Gaunlet. But I'm guessing KR you meant co-op shooters?

I've heard the Marvel Ultimate Alliance game is kickass

Ultimate Alliance is alright. The only co-op PS2 game I've ever played was Champions of Norrath, and I loved it.

I'm more of an old school co-op guy. Contra, Gunstar Heroes, R-Type. That sort of thing.