Random Argument Man said:
-Pretty much anything AC related.
-I also like the Gun Game mode in Call of duty. It forces you to change gaming style.
However, who can compete with classic co-op?
I love co-op! : D especially when it's both splitscreen and online because the dev could be bothered to has both. (Obligatory mention of how much I love Resistance 3.)
My faves?
Rush in Bad Company 2, it's just so fucking fun with a couple of friends and some explosives. I mean, who doesn't love piling up anti-tank mines behind their friend on a quad bike and catapulting them across the entire map? My favourite multiplayer game ever, I must say.
I loved
One in the Chamber in Black Ops, because it suits me to a T, one shot one kill, and a knife. Simple but oh so satisfying when you play mind games on it.
Spec Ops from MW2 and 3 get special mention because I loved playing through missions with a friend and they offered a good challenge. Except Jugs in the Favela, that was too far but damn it I beat them anyway.
Resistance 3, co-op, multiplayer and the best motherfucking horde mode I can think of (GRIIIIIIIIIIIIIMMS! Hundreds of the bastards!)
I love me some
Warzone in the Killzone series, I love how the mode cycles and keeps you on your toes, changing up the mode and forcing you to adapt to survive.
Openworld co-op is always welcome to me, particularly
Saints Row 2 and I feel that it's all that was missding from
Just Cause 2.
Borderlands gets an honorable mention because it's a multiplayer only game and I refuse to believe otherwise, and the same goes for
Left 4 Dead 2.
I'll leave it there for now =]
EDIT:
Gotta add in that I also love me some
Conquest/Domination in both Battlefield (especially BC2) and Call of Duty, and any similar mode is great fun for me.