I started with the TRS80 at the Tandy store, I learned Z80 assembler and BASIC (the early form of it)...
I got a Z80 "box" from Dick Smith which ran CP/M from 5.25" floppy disk... CP/M came with assembly source code, so it was very interesting seeing how to write device drivers...
then I went to uni where I learned stuff like 6800 and 68000, hardware (analog and digital) and software (C and Pascal)... when I got a full time job I worked on 68K stuff alot, and then slowly after switching jobs a few times somehow ended up doing 386+ stuff... I hardly touch application code, I mostly do driver code (in linux).