I can understand getting rid of some games. Looking at my PC shelf, Battlefield 1942, Battlefield Vietnam, Call of Duty 2, Country-Strike Condition Zero, Dungeon Siege, Everquest II, Fable, Final Fantasy XI, Medal of Honor Allied Assault, Myst V: End of Ages, Star Wars Galaxies: An Empire Divided, Unreal Tournament 2003, and Vanguard: Saga of Heroes are all games I could very very easily do without.
Some games I have are older than all of them and I wouldn't give up for anything. My 10 copies of Super Mario Bros (rough estimate), Super Mario RPG, Super Metroid!