[quote name='IAmTheCheapestGamer']bumpage, would like to see more peoples game collections listed...don't be shy....[/quote]
If you insist... I have lots of moedrately rare stuff, but I'm happiest about these:
Many PS1 RPGs are highly sought after, and although I'm selling several, I've still got the Arc The Lad Collection and the two Lunar games (including all the preorder bonuses Working Designs threw in). I'll never sell those. I still have the original Valkyrie Profile, too.
On the PS2, Growlanser Generations (the deluxe edition, plus the preorder bonuses), and all the not-a-big-deal semi-rare "gamer's games" like Ico, Shadow of the Colossus, Okami...
All four Silent Hill games, all three Fatal Frames, and all the GameCube Resident Evil ports. Not all are rare or even valuable, but I'm glad to have them all.
On the PC, I kick it old school with Masterpireces of Infocom, The Ultima Collection, and the Interplay 10th Anniversary Collection.
My biggest rarity moment was that I got Swordquest: Waterworld for the Atari 2600 when it was first released (yeah I'm that old); however, that was sold in a garage sale by my parents many many years ago.

In hindsight, the Swordquest games were really really crappy; the very common Adventure was head and shoulders above.