I literally have never spent this much time on a poll before.
Tastebuds and sinuses are out.
Eardrums? I'm young, I can hear pretty well right now. - Out
Knee caps or shoulderblades?
Well Electronics generally fail, but I am guessing that both of these require some wiring or there would be no use for either.
Solar power would be nice, but then I would have to sit out in the sun with my shirt off all the time. I know ladies, calm down.
I'm going with the knee caps, maybe I could jump like a spring or run really fast? At least help me lift really heavy things?