PS1 Valkyrie Profile and FF7.

Price-wise, I think a mint condition copy of Chrono Trigger with all the correct packaging.

Other near-and-dear new treasure is a mint copy of Herzog Zwei.

I have a few not sure which is the rarest though.

Chrono Trigger for Snes.
Ikaruga for Dreamcast and Gamecube
.hack//quarantine for ps2 (just got it today :D
Final Fantasy 3 for Snes ( i get so giddy when Terra's Theme plays!

Hmm... pricewise, I'd have to guess Suikoden 2. That one set me back about $135, but I so wanted it! But for sheer rarity, it'll go to the Japanese Chrono Trigger promotional demo. It only set me back $80, but I saw it, and simply HAD to have it!

My nes collection

I'm not really sure if any of the games I have are rare. I know that the Arc The Lad games for the PS1 can be pretty hard to get and the first Shadow Hearts is pretty hard to find to.

Lunar: EB
Lunar: EBC
Lunar: SSSC
MVP Baseball 2005

All 4 are pretty much ~60$+

Now? Probably Metal Gear Solid Twin Snakes, F-Zero GX, Viewtiful Joe (didn't sell too hot), and Star Wars Jedi Knight 2 on the Gamecube

Prior to my house fire I had quite a few, mainly my Earthbound game worth around 200 dollars :'(

Yggdra Union (GBA) or P.N.03 (GCN)?
Sure you can find them on ebay for not that much but I dont think in stores they are rare.

I don't think FF7 is considered rare. My grandpa's giving me his old SNES games soon to add to my collection. Which includes Mario Kart and Pilot Wings. It will be a fine day for me indeed.