Unless it's a current gen system or a brand new game, I don't see the reason to sell my video game stuff. Even rare stuff, like my mint copy of Burning Rangers or some Dreamcast rarities, I could technically make a profit off of, but then if I'd ever want to play them again I'd have to pony up the same amount of cash to get them back.
Yeah, I'm a hoarder like MadeMan. The games that I wouldn't mind parting with are so shitty and cheap, that should I sell them I'd get a few bucks at most. I'm looking at you Platinum Hits Sonic '06, SEGA CD Double Switch and 360 copy of Blue Dragon that I earned with Kartel Karma points! Eh, not worth the hassle, might as well keep 'em.
I have a fat PS2 and two Dreamcasts in my closet, an NES, Genesis, 32X, SEGA CD, Dreamcast and XBOX 180 in the back room. 360, PS2 slim, Dreamcast and Saturn in the living room. About three drawers of controllers and a tall shelf of all my games that would probably fall and kill me someday. PlayFire.com says I have around 400 games on that shelf. Scary stuff.