Quite a few, actually. Off the top of my head though:
Counterstrike
Team fortress 1 and 2
Unreal Tournament and UT 3
Diablo 1,2 and 3
Arena, Daggerfall, Morrowind, Oblivion, Skyrim
Baldur's Gate I and II
Icewind Dale I and II
Mount & Blade
Heroes of Might & Magic I, II, III and IV
Might & Magic 6, 7 and 8
Betrayal at Krondor
Final Fantasy VII, VIII, IX, X and XII
Gran Turismo 1, 2, 3, 4 and 5
Swat 4
Call of Duty 1 and 2
Borderlands 1 and 2
Deus Ex
Gothic II and III
GTA 1, 2, 3, Vice City, San Andreas and IV
Dungeon Siege 1 and 2
Eador: Masters of the Broken World
King's Bounty: Armored Princes and Crossworlds
Neverwinter Nights 1 and 2
Risen
Sacred
Starcraft I and II
Warcraft I and II
Civilization 2, 3 and 4
Colonization
Sim City 2000 and 3000
Terraria
Worms
Super Mario Bros 1, 2 and 3, Super Mario 64
Mario Kart 64, Super Mario Kart
Zelda: Ocarina of Time and Majora's Mask
Resident Evil 1, 2 and 5
Goldeneye 64
Lands of Lore 1 and 2
Ultima Underworld: The Stygian Abyss
Temple of Elemental Evil
Stone Prophet (Ravenloft)
Carmageddon 1 and 2
Delta Force 1 and 2
Can't remember any more, there are probably a few more I haven't mentioned though. And; yes, I like to get games with lasting value and I replay the classics fairly often. 
