Tried to give a range of titles from my gaming past and present. Some of them come from sheer time played as well as the good memories from doing so (Halo 2's co-op campaign memories just about lose out to Halo 3 MP memories).
Decided to pick just one title from a given series to save on space; considering I didn't get all I wanted on there anyway.
Tried to rank them but that it's almost impossible; just too mind-boggling a thing to do.
1. Halo 3
2. Rock Band 3
3. Burnout 2
4. GTA IV
5. TimeSplitters 2
6. Carmageddon
7. Final Fantasy VII
8. The Curse of Monkey Island
9. Tekken 3
10. Knights Of The Old Republic
11. Pokemon Silver (and Gold, obviously)
12. Sonic 3
13. Need For Speed III: Hot Pursuit
14. Duke Nukem 3D
15. Unreal Tournament
Honourable mentions to:
TMNT II: The Arcade Game, Chip N' Dale Rescue Rangers, Mass Effect games, Age of Empires II, The Sims, Theme Hospital, Uncharted 2, LittleBigPlanet 2, Freedom Force, Vigilante 8 and Psychonauts.