I think every time I do a top 10 games it changes but here goes - as always 1 game per series. The system I played it on is in brackets
1. Gran Turismo 4 (PS2)
2. Call of Duty 4 (360/PS3)
3. Pokemon Red/Blue (GB)
4. Crash Bandicoot 3: Warped (PS1)
5. Any of the old EA NHL games from 1997-2005 and 2009 (PS1/PS2/360)
6. The Sims (PC)
7. No One Lives Forever (PS2)
8. Rainbow Six: Vegas (PS3/360)
9. Fallout 3 (360)
10. Grand Theft Auto: Vice City or San Andreas