I'm a collector of RPGs mostly (I buy every RPG released, regardless of how good or bad it is), but I never sell any game I had fun with. I prefer to focus on world-jumping and enjoying as many stories and adventures as I can, and don't get tied down to mastering one game. Currently, my Xbox 360 library is neatly shelved, separated by genre, in alphbetical order, with any special/limited/collector's editions in a plastic wrap.
Current population of my Xbox 360 wall is 187.