I have a 13 yr. old who's kind of picky. She's not really into the fads like most her age. She likes to read- but has all the Potter books; I need something on the "different & not-so-conformist" side! It seems she changes her mind from one wk. to the next! She's also not into video games, tech. stuff, etc.
You could try gifts that are related to books - Harry Potter shirts, etc.
Also, there are a lot of fun science kits that are perfect for teens - everything from "Tasty Science" to "Spa Science" to general "Magic Science" and things like that. Search for Scientific Explorer kits - there are a ton of them. There are even mini-CSI kits out there.
I second the Eragon books, and she may like Twilight (though those books tend to be love/hate). Lord of the Rings?
My daughter seems to be similar to your daughter. My 13 yr old loved the Island of the Blue Dolphins and all the Scott O'Dell books. Another series she liked was the Seeker Series by Erin Hunter. This is a series relating to animals. If I were you I would read the Twilight series first as they get into sexual issues and social issues you may feel your daughter might not be ready for. I have read many a vampire series and once I got into them realized they were really what I would consider more adult than teen books. If she's really into books and you can afford to, I love the Kindle. That way she can store a lot of books at once and the books are a lot cheaper when you get them in this format. Other gifts could be things related to pictures. My daughter liked her camera and small keychain that held pics so she could show her friends. Also if she has a cellphone maybe a cellphone cover in bling. Another suggestion are art and craft items, such as bling or paint your own t-shirt, make your own friendship bracelets and the like. My last suggestion to you is instead of lots of "stuff" our family takes a family trip instead. They get one gift from their siblings and one from mom and dad. We've gotten some great deals during the time the kids are off school and they remember the trips far more than the stuff.