have everyone pitch in and get her a piano tuning or something for christmas.
I think that you have good intentions, but this can come off as pretty insulting. Is her piano badly out of tune?
My all time favorite was a check.
My personal favorite would have to be the spa treatment.
I had a student whose mother owned a local day spa--so I got a massage, facial, mani/petti, and a skin treatment--and it was awesome. They all have gift certificates though and with several different packages. If she is someone who would enjoy that sort of thing and probably not do it for herself--it is a great gift. A gift card for a manicure would probably be appreciated and not too expensive. Maybe a note saying that her hands deserve some special treatment after all that time spent at the piano--... (my spa treatment gift came with a similar message).Like I said... I love the gifts from my students no matter what they are--as do most other teachers I know. It is the coolest time of year to teach piano really--they have their recital, bring you a gift then you get to be off for the next two weeks. It's great!