[antiRepublicrat]

First used (IIRC, a PDP-11, I was a little kid then and my mom worked in a datacenter, the programmers were friendly and let me mess with it)

First owned (Atari 400)

First PC used (IIRC Zenith 8086):

After that, bought a 486/66. Doom rocked on that machine.

[dts32041]

My gosh I performed tech support for that machine.

[Ignatz]

Hey! We had an Atari 400 too! I forgot. I guess I didn't really think of it as a computer, although we did have the BASIC cartridge for it, and I learned enough to write a crappy game program.