Opposite story here... I still use my TI-89 (or my even older TI-86) from time to time, even when sitting in front of a PC that has R, Maxima, Gnuplot, Axiom, Sage, etc. installed. There is something about the format of those old TI calculators that I find oddly appealing for whatever reason.

That said, when I don't have a hand-held calculator handy, I usually just fire up bc or R when I need to do some quick calculations.