Well, I just picked up a C128D in its box with datasette and tonnes of games, manuals, etc all in original boxes and in mint condition (it's the plastic one with the handle, not the metal one) for $10 AUD ($5 US) :-D So I'm happy with that.
I would like to add an A3000 or A4000 to my collection though. I'd also like a Sega Nomad (not quite so retro, or a computer, but still I'd like one). I've got a great Game Gear collection (I have about 5 of the handhelds themselves and 3 TV Tuners) but I'd love to track down a Nomad sometime.