I'm not a huge fan of the type of coop game where everyone has the same goal and play in turns, as they tend towards one better person taking over (except for Flashpoint because OMG FIRE IS EVERYWHERE AND WE'RE DOOMED) even if they don't try to initially. However, there are games that avert this,
Shutupandsitdown- a fantastic site for all your board game review needs plus occasional crossdressing - recommends Space Alert, which is a great co-op game which has so much depth and also Escape: Curse of the temple, which I haven't played but keep meaning to pick up, both of which use real time to make everything hilariously fun (and just plain hilarious). Arcane Archer brings up Settlers, which isn't exactly coop, but isn't mean enough to make anyone feel bitter and there are a few others like that, though none come to mind right now.