Army of Two: Shanghai Noon

Army of Two 40th Day came out a long time ago, but I never picked it up because I didn't have anyone to play with.  A friend and I played through Army of Two a good long while ago, and it was fun to play with a buddy just because there weren't any good co op games out there, but didn't exactly knock my socks off.  The weapon customization was nice, but really just ended up making one of us make our guns super aggro machines and the other reverse aggro machines.

Aggro works just like it does in most MMO's... the more you have, the more the enemy shoots at you and not your partner.

40th day is a lot more fun than the first one.  We're both pretty even in our aggro loadout, and we don't feel like we're losing out tactically.  You can also now pick up enemy's dropped weapons, so if I need to I can grab an unsilenced rifle to hold their attention so my friend can flank.

All in all, it's a great co op experience.  Not so sure I'd be as happy with it if it were a computer AI as my buddy.  We've run into some frustrating moments, but nothing so bad we put the controller down.

There are some other neat gameplay additions.  We've gotten separated more than once, and they don't feel like "oops, we're separated... sure hope we don't die".  There's also a new morality and comraderie system, with rewards and penalties for going one way or another.  There's also a bonus for rescuing hostages, in both money and free parts and sometimes even guns.

All in all, I like this game a LOT more than it's first installment.  If you have a buddy to play with or wanna chance a random buddy in xbox live, don't be afraid to pick this one up.