Sweetblood by Pete Hautman. This is for young adults, and subtitled: A Vampire Novel. The way the vampires come into it is great. I'm sure I heard about it from bookshelves of doom, but probably also from some other sites, because I'm sure I've seen multiple discussions of it.
It's about a Lucy, a diabetic. Her theory is that vampire legends are based on diabetics -- and her paper stating that starts to get her into trouble. The book is really about her becoming comfortable with herself. She's great at being sarcastic about being a teenager: "I add four packets of fake sugar to my latte, then go looking for a table where I can sit and act blase."
I thought the writing was very good. Some of the phrases were very evocative and reminded me of when I was younger and how I viewed my future: "I don't smoke, but when I imagine myself independent and on my own I always see myself smoking nonfilter cigarettes and drinking straight espresso from a small, cracked cup."
I also loved the idea of Bizarro Halloween, where all the goths dress up in chinos and polo shirts and/or cheerleader uniforms.