I don't know what a gamertag is but my XBL name is ICU27. I play mostly Gears, and occasionally Halo 2 if invited. I've only been beaten by one person, and our matches are pretty close. I'd love to see how skilled some people are.
I play; Pro Evolution Soccer 6, Gears and that's about it. I've sold most of my Multiplayer games because I'm a fool and a half. But, Halo 3 on Wednesday. So I'll see you there for 4 player Co-Op. =]
Mine is the same as my ZU name, I Nintendude I, formerly IXx Wii60 xXI. I have a bunch of 360 games, but the only one I play regularly is Gears of War (I'm a mean snipe! ), but I'm happy to play Halo 3 if invited to.