"Angelfire" by Courtney Allison Moulton

"When seventeen-year-old Ellie starts seeing reapers - monstrous creatures who devour humans and send their souls to Hell - she finds herself on the front lines of a supernatural war between archangels and the Fallen and faced with the possible destruction of her soul.
A mysterious boy named Will reveals she is the reincarnation of an ancient warrior, the only one capable of wielding swords of angelfire to fight the reapers, and he is an immortal sworn to protect her in battle. Now that Ellie's powers have been awakened, a powerful reaper called Bastian has come forward to challenge her. He has employed a fierce assassin to eliminate her - an assassin who has already killed her once.
While balancing her dwindling social life and reaper-hunting duties, she and Will discover Bastian is searching for a dormant creature believed to be a true soul reaper. Bastian plans to use this weapon to ignite the End of Days and to destroy Ellie's soul, ending her rebirth cycle forever. Now, she must face an army of Bastian's most frightening reapers, prevent the soul reaper from consuming her soul, and uncover the secrets of her past lives - including truths that may be too frightening to remember."-goodreads

Angelfire was action packed! There were crazy awesome fight scenes. But those aren't the only elements that made Angelfire such a great book. An interesting cast of characters and a rather unique plot contributed to the awesome as well. I liked Ellie and Will individually and then, awww. I also liked Ellie's mom, which is random, but it's actually kind of significant because so often in YA we find the mom that we hate or just feel indifferent about and there usually aren't likeable moms or dads (granted, the dad wasn't likable. At all. But I won't rant about that.). The characters were each quirky in their own ways, from Ellie naming her car Marshmallow to Will's thing for root beer floats. I appreciated how the monsters and the reality of their presence actually complicating Ellie's life and her social life. Sometimes, in the paranormal books, the character is fighting monsters at night and in the day everything is perfectly normal, no changes, which isn't realistic... The reincarnation aspect was interesting, and I'm curious to find out more about that and Ellie's memories in the sequel. The sequel, Wings of the Wicked, comes out in February 2012. (Which is almost forever from now *exaggeration* but I'm excited for it!)