I'm pretty sure there's a lot of collectors of old video games in here, so here's my question:
What is the most treasured part(s) of your collection? The Neverhood boxed? Collector's Edition Baldur's Gate II? The Great Giana Sisters? Maybe your complete collection of the LucasArts Classic Line? Show us the good stuff!

For PC games, my The Neverhood with manual and case (I didn't know it came with a box...)
If you mean gaming in general, my Punch-Out!! garbage can I got for 50 cents at a yard sale.

Sam and Max hit the Road in its original box

I have no idea whether it came in a box actually... Haven't ever really searched too much for it...
And the garbage can sounds awesome! Got a picture?

My complete Harpoon (original version) collection.

Secret of MI CD Version, Day of the Tentacle Talkie, Sam and Max CD version, Grim fandango, Curse of MI, Boxed Baldur's Gate Collection, Fallour Collection...

*envious*
To my great shame, I do not own Hit the Road... but I have almost everything else.

Here is the only picture I could find of the garbage can. Imagine mine slightly more dented and dirtier.[url=]http://bulk.destructoid.com/ul/user/1/16938-127768-canjpg-620x.jpg[/url]
The Neverhood looks like it may have came in a box. The case has no description on the back, only a CD key, copyrightstuff, and logos. All the cover says is "Embark on a clay adventure that breaks the mold".
Also, another thing I have to make you guys jealous: A boxed Commodore 64. Unfortunately, no cables or a screen or anything, not even a manual.

OMG OMG OMG!!!

My very own Magnavox Odyssey² (or Philips Videopac G7000 in Europe), still in perfect working condition.
Gunfighter is probably the best multiplayer game ever made. Great fun during the traditional norwegian weekend binge drinking.

I think the rarest thing I have is my boxed copy of Infocom's Planetfall for the Amiga.
Also, I'm very fond of my original breadbox C64 and my 48k Spectrum, even if they are in a box under the stairs.

Gaming... dunno really. I mean, It would take a lot for me to give up my Myst III: Exile Collector's Edition or my Swedish version of The Longest Journey, but the complete collection of Infinity Engine games (only Baldur's Gate is a too recent edition to be on CD's), both Knights of the old Republic games (the first one took a while to find), The Witcher, World of Warcraft and both expansions as CE's, and most of my other games have a definite place in the collection. The only ones I'm pretty sure I wouldn't miss are Wizardry 8 and Caesar IV.
Semi-related to games, I would probably say my old Macintosh Performa 475, upgraded from the original 150 MB HDD and 4MB RAM it had in '94 to a respectable 4GB HDD and 36 MB RAM it now serves as a host for my SCSI scanner and works at least as well as it did back then. The 25 MHz 68LC040 processor still doesn't do floating-point calculations, but I bet I'll scrap my 3 GHz Athlon X2 with 8 GB of RAM and 3 TB HDD space before my first machine bites the dust.

All of mine are flawed treasures.
- Dune 2 cardboard box, but from an HitSquad edition,
- Fallout 2 cardboard box, but with a PL VERSION imprinted on it.
- WarCraft II cardboard, but from the battle net edition.
- A Commodore 64 cardboard box [with a polish imprint saying "NEW! with polish user manual", yeah, i love someone prints "new" on something, can't wait for it to get old.
And since many c64 users actually sold or gave their hardware away, i've got to say that my biggest treasure is my first computer ever, introduced to me whan i was 3 or 4, the Commodore 64 [BreadBox one].;) i recently got a fully working c64c, that's the slim one.;)
Proud as hell of them i am, yarr! :D
Too bad my brother got rid of my second computer, the IBM XT. Cute inferior little machine.. ;P

I primarily collect PS1 games.
Vanguard Bandits. My god this game is a bitch to get a hold of.
Team Buddies.
Legend of Dragoon
Kula World
Trying to get my hands on Tactics Ogre, Let us Cling Together

The whole bunch of it?
If I had to settle on a particular item, it's probably my Starflight collection (first one with 2 different box sets), followed by all 3 Bard's Tales and the lost treasures of Infocom 1 and 2.