This is my oldest one:

http://www.old-computers.com/museum/....asp?st=1&c=29

It is the BBC Model B. I have the 32kb expansion card for it and the original colour monitor.

I also have one of these:

http://www.old-computers.com/museum/...asp?st=1&c=286

IBM PCXT 640kb RAM, 10Mb HDD and a greenscreen.