Darkly Dreaming Dexter by Jeff Lindsay
I actually only heard of this book due to the Showtime series, Dexter. I was actually surprised by how closely the series seemed to follow parts of the book. The first hundred pages of the book were used almost word for word in the first few episodes. This is one of the few times that the adaptation was more developed than the novel, but that's the difference between making a film and a series - there's actually the time to develop everything. The novel also takes place in a shorter period of time, and doesn't have as many plot twists and points to it. It was an entertaining, light read, but I am very impressed with where the show ended up taking it and how they fleshed it out.
For example, I much prefer the character of Laguerta in the show to the woman she is in the novel. At first she is incredibly political and slightly incompetent in both, but as the series progressed, Laguerta actually became a very sympathetic character, who is also a competent cop, if she's occasionally gets too wrapped in the politics of it all. She never really gets beyond dumb and incompetent in the novel.
I also have no clue how much of the second novel was incorporated into the show (during either season), but from reading the synopsis, it definitely sounds nothing like the second season of Dexter. It was a pleasant way to spend an afternoon, but I'm in no rush to read the rest of the series. Maybe if I happen to see the second one in the PX or hit another reading lull, I'll get it, but until then, I have other books I'm more interested in.