Through most of middle and high school I used a circular slide rule. In senior year I used money from my grocery store job to buy an HP45. When I got to engineering school, one professor insisted that pocket calculators were a fad, that circular rules were not good enough, and that I had to buy a straight rule. The local engineering supply had, for a while, taken top-quality rules in trade for calculators. So I was able to pick up a used Dietzgen 1734, with a mahogany core and teflon bearings, very cheaply. I still use it in my CS classes, as an example of 0th generation computing technology. It is still in its orange box and leather holster, with the manual wrapped around it. 

Early computers I've used and/or programmed include: IBM 360/20, 360/40, 1130, 1620, PDP 8/L, 8/E, 8/I, 12, VAX 11/780, CDC 3300, Cyber 74, Cyber 180. Also a research machine using a glass delay line associative memory in combination with surplus core memory units from the IBM 7030 (I still have some of the core planes, drivers, and manuals). The 3300 had the coolest console of any of them, with rows of projected octal digits. The research machine had the weirdest instruction (skip on sunny Sundays). 

Chip