PS2:
1. Final Fantasy X
2. GTA: Vice City
3. Gran Turismo 3
4. Champions of Norrath (brilliant co-op and huge game)
5. Timesplitters 2 (best local multiplayer console shooter since Goldeneye 64)
6. Colin Mcrae Rally 3
7. Metal Gear Solid 2
8. GTA: San Andreas
9. Silent Hill 2
10. Jak & Daxter
Or something like that. Hard to make a top ten, would be easy for me to fill in a list of 30-40 great games for this system.