I assume you mean machines that are worth more than their original purchase price. That would be a pretty short list... notably: - IMSAI 8080 (assuming a base system; a fully configured setup would have cost thousands) - MOSTech KIM-1 (it was so cheap originally it can hardly avoid appreciating since it's a significant historical piece) - Rockwell AIM-65 (ditto) - RCA COSMAC VIP (ditto) If we adjust 1970s dollars to today's rate, not even the Altairs go for more than the purchase price. That leaves only the Apple I in the appreciating column. The only other micro systems (besides the Altair 8800s & Apple I) that fetch significant money, but are nowhere near appreciating from original cost, are: - IBM 5100 - Altair 680 - Processor Technology SOL - Commodore PET (chiclet version) - Apple Lisa - Unproduced prototypes of Atari 8-bit or Commodore equipment Kai

The only other micro systems (besides the Altair 8800s & Apple I) that fetch significant money, but are nowhere near appreciating from original cost, are: - IBM 5100 - Altair 680 - Processor Technology SOL - Commodore PET (chiclet version) - Apple Lisa - Unproduced prototypes of Atari 8-bit or Commodore equipment