First Grave on the Right by Darynda Jones

Charley Davidson (yes, like the motorcycle) is part-time private investigator, part-time police consultant, and full-time Grim Reaper. When spirits don't immediately pass on to the other side, they find their way to her. Whether she likes it or not, she has to help them work through whatever is holding them here and help them cross over. Usually, this is fine, but lately, there's been something else bothering her. Every night, she's been having wildly erotic, incredibly vivid dreams, and every day, she's been seeing mysterious dark blurs just in the fringes of her vision, like something is stalking her. She thinks the two must be connected, and might also be connected to the most terrifying night of her life-- the night she met the inhumanly strong, inhumanly agile, inhumanly gorgeous boy called Reyes. But apparently the whole world thinks it's "Kill Charley Davidson Week," so first she'll have to survive long enough to find her answers.

If you're looking for a new mystery series to start, especially if you're a fan of Stephanie Plum, Mercy Thompson, or Sookie Stackhouse, this would be a good one to pick up. The writing is snarky and energetic, and while the first book is maybe trying a little too hard to keep a constant stream of jokes flowing, it's still a very funny, very engaging book that is easy to read in a few short sittings.