My personal Holy Grail is a complete set of the original Infocom titles for the good 'ol TI-99/4A. I only came to this realization recently. There's something so cool about the text experience, and the Infocom guys really knew how to augment it with 'feelies'. Plus, the TI got to hang with the big boys (Apple II, C64, Atari 8 bit, MS-DOS, etc.) on those early titles--too cool.
I'd also like to pick up a copy of Dragon's Lair. It's such a technical achievement. Unfortunately I had way too many bills at the time it came out. Ah well, now I get to hunt for one.