QB4.5
QuickBasic 4.5 for me - I still have the manual.
One of my very few claims to fame is that I wrote the interpreter in compiled QB4.5 for a high level interpreted language (which I also created) used for developing touch screen applications, Mind you, this was in the eighties when touch screens were indistinguishable from magic, and when there were actually a lot more diverse technologies than nowadays. We sold a few copies though.
Oh, sorry - it's new technologies we're looking at (goes back to shaking fist at clouds ...)