Some of my book friends read a lot of young adult. I don't read near as much, but I do have some favorites. Many of my YA favorites are novels by Sarah Dessen.
The Truth about Forever was the last Dessen book I hadn't read. Luckily, it was worth waiting for. The book has some similar themes to Dessen's other books (some loss--a divorce, death-- summer time, dreamy potential boyfriend--where were guys of this quality when I was in high school?!), but are fresh in each book.
After having read all of Dessen's books, I think my favorite is Along for the Ride. The Truth about Forever, Just Listen, and Lock and Key are tied for a close second. The first one I read was This Lullaby, which I picked up because my friend Jessica raved about it. I wasn't thrilled with it when I read it, but I've decided to reread it since it was the first non-Twilight YA book I'd read in a long time. (Not that YA books aren't as good, they are just different.)
If you've been thinking about picking up a YA book (other than Twilight) definitely pick up one of Sarah Dessen's. Or Meg Cabot or Megan McCafferty.