Let me cheat on this one....a bit
Funny.. I saw 'Fading Suns' on someone's list. Years ago I bought it, read it, was mildly interested by it, tried to play it with some buddies, and we unanimously renamed it 'Fading Interest,' and the poor thing ended up on eBay.
Okay, so that's a little cheating; now here's to the dust-gatherers I own:
Dragonstar (what was I thinking?)
Traveller d20 (loved the little black books..can't seem to rekindle the flame)
Call of Cthulhu
Chill (by Pacesetter! does it count that I bought it on eBay and have yet to play it, even though I did 20 years ago?)
Star Frontiers (see comment for Chill...damn those players who won't take a nostalgia trip!)
Hunter Planet (dubbed as "The All-Australian RPG" it's a tongue-in-cheek take on Predator, in which PCs are the hunters...probably good when drunk, but I wouldn't know for sure)
Star Trek -- the LUG version...own WAY too many books for that, but damn those players who won't step out of fantasy worlds!
DC Universe RPG, by WEG
Advanced Marvel Superheroes
...and I once owned WEG's 'The Price of Freedom,' which was their take on that movie Red Dawn...had a great automatic fire mechanic in the combat system...but damn those players who didn't want to trade marauding goblins for invading communists...!
It's a bit scary, really, when we consider just how many games we own, how many we've owned, and how much money we've spent over the years on them all...and then to consider all the ones we've never played, or only did once because your friends decided to humor you and agree that MAYBE Palladium FRP was better than DnD (well, better than 2nd ed, right?).
Good gaming, all....