I guess it would be my programmable scientific calculator when I was a student. You could write some quite complex operations on it, but it was tedious. We had Commodore Pets in the labs, and the big computers were DEC somethingorothers. We still used punch tape from some of the instruments. This was the early 80s.
Oldest computer I've worked on was probably an IBM Series/1 (the serious-one) which dated from the 70s and was a beast of a thing to program. I didn't have a clue what I was doing most of the time. The expert was a bloke called Terry knew everything and smelt of boiled cabbage.
But I never actually owned a computer until comparitively recently. I had enough of them at work.