1975-1985: Altair 8800 (which my father built from a MITS kit, and on which I first learned BASIC programming, using programs printed in Creative Computing--oh, and one of the first BASIC interpreters for the Altair was developed by two kids named Bill & Paul for their startup company, Microsoft.)
1985-1990: Amiga 1000 (one of the early ones, with the designers' signatures engraved on the inside of the case)
1990-1995: Amiga 500 (my first computer that was mine and mine alone)
1995-present: Various machines running various flavors of Windows. (Currently a nice, new-ish Dell.)
One of my earliest memories is of my father tinkering with the Altair in the apartment we moved from when I was four, making it display some text on the original one-line screen he had for it.
(So if anyone tries to tell you that the first people to grow up with a personal computer in the home belong to Generation Y, you set them straight, y'hear? :) )
Feudalism: Serf & Turf