Well, this list will be utterly incomplete, I'm sure, considering I recently traded in 90% of my last gen games at Gamestop, but I'll give it a shot.
PC:
Baldur's Gate
Baldur's Gate: Tales of the Sword Coast
Baldur's Gate 2: Shadow of Amn
Baldur's Gate 2: Throne of Bhaal
Battlefield 1942
Battlefield 1942: Road to Rome
Battlefield 1942: Secret Weapons of WWII
Battlefield: Vietnam
Call of Duty
Call of Duty: United Offensive
Civilization 4
Command & Conquer: Renegade
Command & Conquer: Tiberium Sun
Command & Conquer: Tiberium Sun: Firestorm
Command & Conquer: Red Alert 2
Command & Conquer: Red Alert 2: Yuri's Revenge
Fallout
Fallout 2
Fallout: Tactics
Galactic Civilizations II: Dread Lords
Shogun: Total War
Shogun: Total War: Mongol Invasion
Medieval: Total War
Medieval: Total War: Viking Invasion
Rome: Total War
Rome: Total War: Barbarian Invasion
Rome: Total War: Alexander
Kotor
Kotor II
The Elder Scrolls III: Morrowind
The Elder Scrolls III: Tribunal
The Elder Scrolls III: Bloodmoon
Half Life
The Sims
The Sims 2
(I think I'm missing a few there...)
Gamecube (used to be many more titles here...):
Metroid Prime
Metroid Prime 2: Echoes
Pikmin
Super Mario Sunshine
Wave Race: Blue Storm
Paper Mario: The Thousand Year Door
PS2 (same thing, I sold many games):
Tony Hawk's Pro Skater 3
Tony Hawk's Pro Skater 4
SSX
SSX Tricky
SSX 3
Splinter Cell: Pandora Tomorrow
Mercenaries
Burnout 3: Takedown
Xbox:
Jade Empire
Halo 2
Fable
Splinter Cell: Chaos Theory
Star Wars: Battlefront 2
PoP: Sands of Time
Soul Caliber 2
Xbox 360:
Bioshock
Mass Effect
The Elder Scrolls IV: Oblivion
Call of Duty 4: Modern Warfare
Call of Duty 3
Call of Duty 2
Half Life 2: The Orange Box
Crackdown
GRAW
Rainbow Six: Vegas
Gears of War
PGR 3
Wii:
The Legend of Zelda: Twilight Princess
Metroid Prime 3
Wii Sports
Super Mario Galaxy
Wii VC:
Sonic the Hedgehog 2
Paper Mario
Super Mario Bros. 3
Super Metroid
PSP:
Wipeout: Pure
Burnout: Legends
Lumines
DS:
Advance Wars: Dual Strike
Pokemon Diamond
Mario and Luigi: Partners in Time
Brain Age
Metroid Prime: Hunters
