Working with middle schoolers, I often see titles cycle through the library. Scott Westerfeld's The Uglies series was big about 5 years ago, then didn't receive much interest. After two books in the series were lost, I decided to reorder. The new covers brought new readers (and boy, are there a lot of different covers for this series!)
Tally is about to turn 16, when she'll become Pretty. She's killing time, waiting to be reunited with her friend who is already Pretty, when she meets Shay. Shay is not interested in becoming Pretty, and is set on avoiding the surgeries that make it happen. Tally initially is confused why anyone wouldn't want to join the Pretties, but she's disturbed when she crashes a Pretty party and sees what goes on. She joins an underground group of resisters called the Smoke, but after their capture, decides to go through with the operation to become a Pretty.
The trilogy takes Tally through being a Pretty, and enjoying that mindless existence, to becoming a Special, a high level fighter who keeps the Uglies and the Pretties in line. Through all of this, Tally experiences disturbing reminders of the friends she made in the Smoke.
There's plenty of action here to engage most readers, and many students may find the idea of engineered beauty fascinating. The new covers were designed to appeal to both genders, so don't hesitate to promote to boys who liked The Maze Runner or Unwind.