The first computer I used extensively was in the engineering labs at the University of Colorado. It was an HP, used HP basic language, and had a cassette tape drive.
I also had an HP 41C programmable calculator. It was programmable, so technically I guess it was a computer.
First personal computer I used was an Atari desktop my father in law owned. POS, but it played Liesure Suit Larry and some early games.
First computer I bought for myself was an old original pentium system from Acer. It was their top of the line media computer. It actually had a small subwoofer with the speakers. Onboard graphics rage 128, and I think 256M memory.
Second desktop was my first Alienware.