Sarah Dessen books are popular but become formulaic, so read this one first- it's one of her best. In Sarah Dessen's world, everyone drinks, parties, and smokes pot. Themes are heavily hinted at, then outright explained, a disappointment for those who prefer to find the deeper meanings and make connections themselves. Owen and Annabel have a delightful relationship, interesting in all its twists and turns, but it was the subplot involving Whitney, the anorexic sister, that really captured my attention. Whitney overcoming her problems was much more exciting than Annabel overcoming hers. When I read this as a young teen, I didn't fully pick up on the hints at Annabel's almost-rape.
A word on Sarah Dessen: As I said, Sarah Dessen is formulaic. Fathers are either absent or in the background; mothers are well-meaning but flawed and controlling; the protagonist is cynical or shy until a strange boy comes in and changes her perspective. You could get discussions out of any of these common features, to put a thoughtful twist on it all.
(Sarah Dessen's novels are predictable enough that my friends and I use it as an adjective - "Then he kissed her in the rain! Such a Sarah Dessen moment!"