Bioshock,
Sid Meirs Pirates,
Prince of Persia,
Silent Storm,
GTA SA,
GTA IV,
Nexus The Jupiter Incident,
Alien VS Predator 2,
GRiD,
Bionic Commando Rearmed,
Penumbra Overture,
Fable The Lost Chapters,
Mechwarrior 4 Vengeance,
Mechwarrior 4 Mercenaries,
Hitman Blood Money,
Thief Deadly Shadows,
Battlestations Midway,
Hidden and Dangerous 2 (plus Expansion),
Total Annihilation,
Titan Quest Immortal Throne,
Prey, (DONE)
Medal of Honour Pacific Assault,
NFS Most Wanted,
NFS Undercover,
Test Drive Unlimited (Grinding),
Desperados 2,
Neverwinter Nights 2,
MDK2,
Krush Kill n'Destroy Extreme,
Diablo 2,
TRON 2.0,
Call of Cthulhu Dark Corners of The Earth,
Sacred 2 Fallen Angel,
Star Trek Bridge Commander,
Dead Space,
The Battle for Middle Earth 2,
Doom 3 Resurrection of Evil,
Serious Sam 2,
Beneath a Steel Sky,
Fallout Tactics,
Jagged Alliance 2,
Men of War,
Bandits Phoenix Rising,
The Chronicles of Riddick Escape from Butcher Bay,
Painkiller,
Painkiller Overdose,
Onimusha 3,
Die By The Sword,
Rainbow Six Raven Shield,
Deus Ex,
Tales of Monkey Island 1
I may have finished some of these in the past but I don't remember them enough to justify not playing them again.