My rarest machines and peripherals are:
Mark-8 Minicomputer
Digital Group TVT (designed for the Mark-8)
Digital Group Z80 system
Digital Group 6800 system
Digital Group 6502 system
Digital Group 6501 system
Digital Group Mini Bytemaster, Z80
Kim-1 with early ROR and indirect jump challenged 6502 micro chip
A few can be seen at my soon to be updated site:
http://members.cox.net/oldcomp/my_collection.htm
-Bryan