There should be more of them.
I remember playing a bunch of COOP games in the 8bit and especially 16 bit games (Secret of Mana comes to mind

), and there are a few great coop games for now (Halo, Contra:SS

) - but still, I don't get why COOP isn't a gameplay mode that's available in more games.
Playing Halo and Contra:SS with my brother just reminded me how much more fun it is when you get to scream at the other person to avoid explosions that they are not seeing. Going back to their single player modes bring absolutely no thrill (I don't play Contra alone anymore, while Halo has a full screen in 1 player, so it has advantages over coop

).
Are there any games, besides FF:CC for the GC and Halo 2 that would have coop? Games you've played in the past without the option that you would like to see remade with a coop option?
IMO, COOP is one of the few things that make gaming great.