IBM System 3.
After that, they were (in chronological order):
Atari 800XL
IBM System 3 (with 10 line VDU)
IBM System 36 (with a massive 200MB hard drive and a carousel that held twenty-four 8-inch floppies)
Packard-Bell 8088
At that point, I jumped into the x86 architecture with an IBM PS/2, 386, and the lovely Microchannels bus (that was incompatible with anything, sometimes seemingly with itself).
