1. Mass Effect
360 - In most ways i liked this game better then ME2, but Mass Effect 2 was a much smoother experience and continued an allready great story in an awesome universe.
2. Forza Motorsport 2
Probably the race game i've played for the most hours, and one achievement short of the full 1000 points. That 1,000,000 online credits achievement was just bullshit!
3. The Orange Box
360 - TF2 on the 360 is kind of sad compared to the Steam version and i've tried a bunch of times to finish Half-Life 2. The reason for this high score is soley because of Portal. Although it was some time later when i really started to enjoy Portal for all its greatness, this could have easily be my number one.
4. Halo 3
360 - The first 360 Halo game was not the "greatest thing ever" (mot by far), but it was still a pretty good game, that i fairly enjoyed.
5. Assassin's Creed
360 - This game did something no other game had done, playing an assassin in a huge open city. Sure AC2 improved in almost every way but this first game was a great start.
6. Call of Duty 4: Modern Warfare
360 (only played the single player)
7. Guitar Hero III: Legends of Rock
360 - My first "fake guitar game" and probably one of the best.
360 - Best skate game... ever?
9. Lost Planet: Extreme Condition
360 - A great game at the time, really frustrating to go back to...
10. Puzzle Quest: Challenge of the Warlords