Susan Ee's
Angelfalls is a good one that comes to mind. Also, Laini Taylor's
The Daughter of Smoke and Bone is a really good one, too.
And there is also a series of "Fallen Angel" (nephillim) books called
The Fallen by Tom Sniegoski. I actually havent' read this series, but I remember that it was turned into an ABC Family TV series and, even though it was a little corny, there was one really cool concept that it had: Angels wielding Swords of Flame and dueling. It reminded me of Jedi and their lightsabers. So when the angels prepare to fight, they "draw" these swords of flame from out of nowhere and go at it. I believe that it's in the books, too.
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