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Hush, Hush series by Becca Fitzpatrick or Angelfall by Susan Ee is good too. I prefer the latter though. There is a movie adaptation of the book Fallen by Lauren Kate if you're interested but in my opinion that sucked. The book was okay but the film sucked bad.
If you dig Sci-Fi combined with philosophy, i'd suggest Bernard Weber's The Empire of Angels, it is part of a cycle : Cycle of Angels, preceded by the book The Thanatonautes.
I love his books to bits.