Art wise, I guess my most memorable accomplishment would be some graphics I did for my very first client, in Photoshop. So what? Well before that moment I HATED Photoshop and knew nothing about it, but the art app I used (Painter) wasn't good with transparency, so had to dive right into PS. Never looked back
Coding wise would be on the Amiga. When I finally figured out how to code shit using the copperlist! Fun times!
Yeah.. Pascal and Delphi... many accompliments there but I think I've said enough ;p