I'm disgusted by the trade-in mentality. If I don't like a game enough, I trash it, I don't want someone else playing it. I wish I wasn't so careless with my games, I have a fraction of the library I've owned in my life, but I still have a box of 5 1/4" c64 and dos games and two boxes of 3 1/2" dos games.
Never losing/damaging game media was the biggest reason I switched to Steam, between Civ II, III (I still have my Civ I 3.5" disks, I doubt they work though hah.. my Civ IV cd was only readable enough to enable me to buy BTS on Steam), Warcraft II, III, Diablo I, II, StarCraft, Mechwarrior 2 and expansions I probably spent a thousand dollars, and all of the cds I still have are scratched beyond imagination.