It's time to compile a list of Young Adult Books that Adults Will Appreciate (and Hopefully Love).
A (small) beginning:
Feed, M. T. Anderson -- This one is still with me, and I read it years ago.
The Chocolate War, Robert Cormier -- Same thing as Feed. It's a classic for a reason.
The Golden Compass, Philip Pullman -- Um, yeah. When I have an adult fantasy reader who hasn't read it, I'm horrified. And I make them take it home. And they love it.
A Northern Light, Jennifer Donnolly -- Loved the language.
Sorcery and Cecilia, Patricia Wrede and Caroline Stevermer -- Good for fans of Jane Austen. Also great for fans of Diana Wynne Jones, though if they already read her, they're already aware of the awesomeness of YA.
What My Mother Doesn't Know, Sonia Sones -- This book captures the WHOOSH of First Love better than any other I can think of.
Leave your suggestions in the comments and I'll repost the list later.
[Later: The same article has spawned a discussion about the merits (or lack thereof) of YA lit at The Elegant Variation. Seems to me that most of the anti-YA-ers haven't read what they're dismissing, but I could be mistaken. (via Dr. Frank and Jen Robinson)]