What's your best co-op experience to date? I'd rather have you exclude multiplayer FPS shooters where you have to work together, because that's just a little lame. (But if there's nothing else it's fine)

For me it's actually the LEGO Star Wars games on DS. Heck yeah, it was awesome to play that game in the middle of the night with someone else. (And I don't even watch the Star Wars movies!) But it has been so many years that it's probably not so good anymore. 

Secret of Mana on SNES. Best time I ever had when I played co-op with friends and since it wasn't online you even had your friends around you

Metal Slug 3 is a co-op gaming bliss, I'll always pop it in when my friends come by. Resident Evil 5 on co-op is also stupidly fun.

Super Mario 3D World w/ the wifey. :).

Co-op GOTG.

Hmm, Goldeneye 64, Timesplitters 2 and Neverwinter Nights spring to mind. Out of those; I'd go with Neverwinter Nights, for the sheer size, depth and scope, a cool story and a roleplaying system I am very familiar with.

Nice shoutout for LEGO :) I'm playing through LEGO Hobbit right now in co-op.

While it might not be the best co-op experience, my personal favorite is playing through Crystal Chronicles on GCN with my friend. It was a blast exploring towns, buying and forging weapons, and taking down bosses together. One of my fondest video game memories ever.

I'm divided between:

· Pacifist on Geometry Wars 2.

· Campaing co-op in Battleblock Theater.

· Gears of War 3 campaing in co-op.

· Uncharted 3 co-op missions.

All those gave me so much fun and joy with my friends :D

3D World and Nintendo Land for all the drunken shenanigans!

The Borderlands games. They're built as a co-op experience (single player's boring) and a ton of fun when played cooperatively.

Game i have played more than any other in co-op over the years is Streets of Rage 2, so i'll go with that.

Honourable mentions.......

Dead Rising 2.
Guardian Heroes.
Left 4 Dead 1 & 2.
Gears 1-3.
Saints Row 2.
Resident Evil Revelations (Raid Mode).
Various Halo's.