That's probably more on me as she is not spoilt, it would be easier if I could just buy new versions of things she has but she won't let me as she is happy with what she has. I rotated the TV's in the house due to buying a new tv for the room I have my consoles in and there was a 50" plasma going spare and she would not have it as she is happy with her 16" lcd tv.

If she really doesn't want anything, how about just taking her and a bunch of her chums for a meal? :)

I would do that anyway but that isn't a present in my eyes? I'm actually paying to take her best friend away with us on our summer holidays but I can't count that as a present either?

Just ask her!

Take her to see a show in London and then for a nice meal.

A barge pole for unwanted boyfriends/punting

Having been down this road with a teenage daughter, looking back I'd say electric would be much better.
Easier to play for a start, and less painful on her fingers

Concert Tickets?

A Spanish style nylon string acoustic would be a good starting point for delicate fingers. But don't spend big bucks as young lady may show no interest at all.

dl

get her a 15 year old boy (and a pack of three ;) )

Unfortunately she already has the 1st one of your suggestion and I'm hoping she doesn't have the second :)

She sounds like a spoiled brat, just say happy birthday to her and save your money. If she doesn't want anything then oblige her by getting her nothing.

Get her an acre of the moon or buy her a star.

weird

as I sell both of those -- and you get a laser printed certificate too

pm me for details

Tickets to a gig for a band / pop-star she likes
Red letter day with multiple things to do - I did Tank driving, Hovercraft sliding, off-roading, Helicopter riding, and cross bow shooting and buggy mudding. I thoroughly enjoyed it!

Also there's one off flight lessons where an instructor will take you up in little 2 seater, and let you fly it about and take you on a specified route, giving you full control, and letting you guide it in for landing, and only taking over for the final approach - Massive smiles guaranteed!