I got a TI-86 my freshman year of highschool, taught myself the BASIC dialect, etc. Useful machine with a nice menu system (menus sit at the bottom of the scree

I got a TI-86 my freshman year of highschool, taught myself the BASIC dialect, etc. Useful machine with a nice menu system (menus sit at the bottom of the screen, rather than modally filling the screen like a TI-82/83/84). I fell in love with RPN at my first internship, where I noticed a lot of the (mechanical) engineers used HP-12 calculators for most everything. I later bought an HP-48 and, eventually, an HP-50G. To my mind, the HP graphing calculators are the Unix of the calculator world, while TI calcs are more like Windows. Most people use TI, but the HP calculators have a longer lineage, a great if somewhat noob-unfriendly interface, and more powerful hardware (75 MHz ARM processor, 2 MB of storage/512 KB of RAM, SD card slot, and the higher-quality HP keyboard). I haven't used my calculator in a while, but I think that's largely because I'm working with operating systems at the moment and don't need to do more than integer arithmetic. I occasionally reach for my Android phone with the HP-48 app on it, but without being able to feel the keys under my fingers it is sadly lacking.