Pretty much anything Barry says from Resident Evil.

And of course - "Somebody set up us the bomb" and "All your base are belong to us" from Zero Wing

Halo already had 2 games to establish a fanbase for Halo 3. Gears 2 won't match it simply for that reason.

I wish they would just remake the original Secret of Mana and maybe make it 3-D. I haven't enjoyed a Mana game since the original.

Also Super Dodge Ball from the NES - that's going back some years...

I know you were looking for "good" coop games, but here's a site where you can search through all multiplayer games. Use the filters to find what you're looking for.

http://www.xboxmp.com