Here are some links to get you started:
       Best Books for Middle Schoolers (according to 7th graders!)
       Book Me - Personalized reading suggestions from AHML!
Put in the last good book you read into these tools...
       What should I read next? - put in the last good book you read
       Stumble Upon - Works just like "What should I read next?" above
       Your Next Read - put in the last good book you read
       Book Seer - put in the last good book you read

The Open Library - online reading!