Uglies. By Scott Westerfeld.
 
Young Adult book.

 Want to be Pretty?  Tally does, and she's going to get her wish.  On her sixteenth birthday, she'll be given the operation, the one that will make her beautiful.  And she'll be able to join her older friends in New Pretty Town, and party all day, every day.

 While waiting out the long summer before her birthday, Tally befriends Shay. Shay is a maverick.  She doesn't want to become Pretty. She wants to keep her own imperfect Ugly face.

Then Shay runs away, and Tally is introduced to the dark side of her Utopia. She is blackmailed into following Shay, and leading Special Circumstances to the Smoke, a hideout for people who have escaped from the cities and the operation.  Tally finds the Smoke, and learns the frightening truth about what lies behind all those Pretty faces.

 Interesting book, and one that came highly recommended.  It's got all of those things we like for young adult books: a strong, smart heroine, lot of action, no explicit sex and no swearing.  There is even some discreet fun at the expense of the older generation: are they brain-damaged, or just parents?