Does this go for GFWL (Games for Windows - Live) too since we're all gonna be connected?
If so:
GFWL Gamertag: NuclearCrap
GFWL-supported online games:
Halo 2 for Vista (buying in a few days)
Shadowrun (first cross-platform game, can't miss it)
Non-supported (online):
Test Drive: Unlimited
Battlefield 2 w/ all expansions
Battlefield 2142 w/ Northern Strike
GTR
GTR2
GT Legends
Rainbow Six: Vegas
Splinter Cell: Double Agent
Splinter Cell: Chaos Theory
Rainbow Six: Lockdown
Ghost Recon: Advanced Warfighter
Doom 3
Call of Duty 2
DiRT (as soon as it comes out)
Flight Simulator X Deluxe
Delta Force: Black Hawk Down w/ Team Sabre
Delta Force Xtreme
Joint Operations: Typhoon Rising w/ Escalation
Multi Theft Auto: Vice City
San Andreas: Multiplayer
F.E.A.R. w/ Extraction Point
Company of Heroes
S.T.A.L.K.E.R. - Shadows of Chernobyl
Counter Strike: Source
Half-Life 2: Deathmatch
Half-Life Deathmatch: Source
2006 FIFA World Cup