Number 9 of the year is Darkly Dreaming Dexter by Jeff Lindsay.

Now, I'm going to start off saying right away that I've been told repeatedly, from different, trusted sources, that this is not a good book. And in comparison to the Dexter television show, no, it's not good. However, nor is it horrible. It's readable, but you can definitely see where the show improved on it. And after having watched two seasons of the show, it's impossible not to compare the book to the show.
So yes, we have one of those (as far as I'm concerned) rarities where the book is NOT better than the other form of media that has spawned from it.

It is also impossible to read this book now and not hear actor Michael C. Hall's voice for Dexter. But the thing is, even with this v/o, I didn't find book-Dexter very... scary. Oh he tells us he's a monster and he tells about how he's killed (and we see him do it), but there's something about the way he's written that makes him seem less than menacing. Perhaps it's Lindsay's overuse of alliteration that does it, I'm not sure. Dexter's inner monologue is nearly flowery, romantic at times, and somehow, it doesn't really work as it makes him less of a monster that he waxes poetic at the moon and whatnot. Book Dexter has none of the... menace that Michael C. Hall so effortlessly portrayed in the series. It was a bit of a let down.

Also, the book does nothing to set up the ultimate identity of the Tamiami Trail Killer (aka the Ice Truck Killer in the show) and by the time you do learn his identity and his connection to Dexter, you're kinda like... what? Where did this come from? The show, on the other hand, built it up brilliantly through flashbacks and Dexter's remembering and whatnot. In the book, Dexter has dreams, but they don't feel connected to his past, rather it focuses on this idea that Dexter could actually be the one physically carrying out the killings, but in a fugue/somnabulastic state. It doesn't really work.

Basically, I can see why the show was made; there's a good idea in here about a serial killer who hunts other serial killers, but the execution of it isn't very good. The show's writer to the initial idea and ran with it, and then were blessed with an extremely good actor who is easy to root for, but still scares the hell out of you while you do so.