TI-36 solar in middle school. I was absolutely kickass with it. I got an HP-39g in freshman year and then a TI-89 in sophomore year. Even then I was still better with my scientific calculator at doing quick calculations. I was fast enough with the storage and recalls, but once I got to practicing the SAT IIs and using graphs and variables to make life easier, I became a TI-89 master.
I still use a TI-89 today although I've found a TI-83+, 85, and 86 in random places and they sit on my desk for no purpose at all.
My most hated calculator is the TI-30x. They made us buy these POS calculators for Chem. Interesting they spedn the most time in the world curbing cheating and preventing people from storing stuff in the easiest classes but when it comes to upper division, who cares..