1. Halo 3 (not currently playing it, but it's my most played 360 game and it's always a blast).
2. Gears of War 2
3. The Beatles: Rock Band
4. Call of Duty: Modern Warfare 2
5. Virtua Fighter 5
6. Assassin's Creed
7. Mass Effect
8. Bioshock
9. Dead Rising
10. Civilization Revolution
Those are 10 spectacular games. I love them all.