Birthday present suggestions

Okay, I've got about 2 weeks to get a birthday present for my fiance's step-sister, but absolutely no idea what to get her...
It's going to be her 13th birthday, and she spends most of her time on MSN or hanging out with friends... She's not really a goth, and hate's chavs... Last year I just gave her some Music vouchers because Emily and I'd only been going out a few months and I didn't know Cait very well at the time. Now I get on with her really well, and she's like the little sister I never had, but I haven't a clue what to buy her. Depending on the status of a loan application, I'm either going to be shopping on a budget, or money won't be an object, so suggestions from all ends of the financial spectrum are welcome Thanks in advance

Music (listening too and singing) hair and make up, horror movies. They mainly just hang out at her friend's house in their pool...

Gift certificate, Just let her buy her own stuff. Don't spend an obscene amount of money on her, cause she might expect you to spend the same amount of money on her all the time. I'm always upfront with my lil cousin, I ask her what store she likes and either take her shopping there, or get her a gift certificate. She loves it, cause she always gets what she wants, and we get to hang out. (our day usually consist of shopping, eating, movie, and then dinner.)

Get her a M.A.C gift certifercate. She should love it.

Cash.

Seriously.

Nothing says "happy birthday, soon-to-be stepsister-in-law" like a Black & Decker.

Oh goodness, yes. Get her a gift certificate for makeup. Good makeup can be quite expensive, especially on a 13-year old's budget, so she'll love you forever.

Dig this idea.

I was going to suggest a gift certificate.

Panini grill. Everyone needs a panini grill.

Y'know some people say "Give what you would like people to give you"
But I find that statement quite unhelpful, think about it, would your mom like tickets to The Mars Volta?

Emily and I're going to suggest to her parents later that we take Cait on a shopping trip with her birthday money, and let her choose any item she wants as a present and get it for her there and then Thanks for the suggestions folks