And really, how could they not be addicted? Harry Dresden has the voice of a hard-boiled detective AND he's a magic-user. His allies include Bob, a lecherous spirit housed in a human skull; Karrin Murphy, a super-tough homicide detective; Michael, a Knight of the Cross; a vampire named Thomas; and Ebenezar McCoy, a wizard who lives in Hogs Hollow, Missouri. As Harry can hardly walk down the sidewalk without getting into trouble, he has run-ins with vampires, werewolves, the Senior Council (the ruling body of wizards), faerie folk and a plethora of supernatural beasties. The books are smart, hilarious, action-packed and very hard to put down.
If any of that sounds remotely interesting, go ahead and pick up the first book -- you won't be disappointed. I promise.
If you're still waffling, go and read Jim Butcher's mini-bio at his website. That was what hooked me in the first place.
Links to my write-ups of the first five books: