Ok, I updated the list. It is now in a spreadsheet. I know there are more games... keep them coming and I will keep adding them. Help me out here... Some of you play a LOT of games and know what is co-op. Just take the time to post...
NOTE: I am purposefully leaving out sports games because it is assumed most all will have both competitive and local co-op.
NOTE2: I am leaving out fighting games (except SSBB) unless there are others that have a true co-op campaign.
NOTE 3: LOCAL CO-OP ONLY. There are lots that do co-op over the internet. That isn't for this thread.
Keep adding and I'll keep updating the list occasionally.