So which Xbox game has the best Co-Op in it and why?   Please post opinions.    Was just curious wanted to see what people think.  

I have to go with Crackdown because it was so open and you could share techniques to get fun achievements. 

I also think the Rainbow 6 Vegas series has been great when it comes to coop Terrorist Hunt. 

I gotta go withthe Femal Pervert (AKA Sard) on this one... Crackdown is hours of fun with a friend.  My favorite co-op shooter is R6V series also. Terrorist hunts FTW.

Soldan:

I gotta go withthe Femal Pervert (AKA Sard) on this one... Crackdown is hours of fun with a friend.  My favorite co-op shooter is R6V series also. Terrorist hunts FTW.

my reputation precedes me

I like Vegas (1 better than 2, just because of the 4 player coop story mode), and Halo 3. I've never played Crackdown, I hear its great too.

One game that doesnt get much love but I think has awesome coop is Marvel Ultimate Alliance. I love that game in MP. 

About the only thing I REALLY enjoyed about Halo 3 was the 4 player co-op.  Crackdown and Gears are my 2 4* pics picks.

My vote is Halo 3 4 player co-op. Some of my best co-op memories!

MathTeach314:

GRAW2 has more co-op modes than any other game I can think of. From simple elimination of AI (think terrorist hunt in R6:V) to elaborate missions. Every co-op mode can be played with 1-16 players online (yes you can play co-op by yourself and even earn co-op achievements as a single player). Given the number of different maps available and the number of different modes, the co-op fun never really ends.

If you can get past the disconnections then ya it pretty good.   I say Crackdown, Halo 3, GOW &  Rainbow Six games

how is GTAs? I havent tried it yet (but I love the SP). 

My list goes:

RS:V (1 & 2)

Halo 3

GRAW2

Crackdown

Cooperative gameplay (often abbreviated as co-op) primarily refers to a feature in video games that allows players to work together as teammates with the absence of player-controlled competitors.{from wikipedia}

In that case, graw2 fits the bill, as do some modes of GTA.  Having a broken neck, I don't get out much, so I really enjoy shooting the shit with people in a game.  Crackdown fits that description nicely.  You can play the game or just drive around doing stunt jumps, glitching, or making games up.  That's why I play GTA so much, for the FreeMode.  That what makes me so excited about Fable 2, being able to go to a bar, go on quests, or do nothing with your friends.

 Graw 2 has to have some of the best co-op features out there. The amount of maps and modes that are available are unbelieveable. If you plan on doing co-op (mission) its best to keep it to 12 or under. With all the ai enemies and your  teammates there has been some connection issues.

NapoleonCGC:

Cooperative gameplay (often abbreviated as co-op) primarily refers to a feature in video games that allows players to work together as teammates with the absence of player-controlled competitors.{from wikipedia}

In that case, graw2 fits the bill, as do some modes of GTA.  Having a broken neck, I don't get out much, so I really enjoy shooting the shit with people in a game.  Crackdown fits that description nicely.  You can play the game or just drive around doing stunt jumps, glitching, or making games up.  That's why I play GTA so much, for the FreeMode.  That what makes me so excited about Fable 2, being able to go to a bar, go on quests, or do nothing with your friends.

I'll have to agree with GRAW 2 being a truly great coop game and gears of war and crackdown are all excellent coop games...........i really liked Halo 3 4 person coop also.......and the outfit was fun with coop