My 12 y.o. is currently very into the Prydain Chronicles ( a series of 5 books) - he can't put them down! He just finished Watership Down and really loved that one too. He found The Book of Lists for Teens very entertaining. He loved all three of the Artemis Fowl books. The Thief Lord, The Lost Years of Merlin series by T.A. Barron. That's all I can think of at the moment. Try Chinaberry.com - it is a great resource!