I frequently wake up at ~4:00 in the morning and have trouble getting back to sleep until 5:00 - 5:30. I find it helps to have a good trashy read (no, that's not an oxymoron; there's good trash and bad, and you know what I'm talkin' 'bout) to fill this time. I've recently discovered the Dresden Files in book form at my library, and it's really good trash: well written and well crafted. I read an interview online with Jim Butcher, the author of the series, and he was asked about the television series that was made from his characters. He said that the TV series did not closely follow his books, but that was all right with him, 'cause then people would actually buy his books, not having seen slavish reproductions of them on the screen.
Well the converse is true as well. Even though the stories are different, this series has captured Butcher's freewheeling, sarcastic, good-natured, troubled and perpetually off-balance, but above all magically gifted Harry Dresden perfectly, and I enjoyed every minute of every episode. Damn - why isn't there a season 2?
I would say that if you have enjoyed the books, you'll enjoy the series, even though it doesn't exactly follow the books (or maybe because it doesn't exactly follow the series). And if you get this series and enjoy it, try out the books.
I've read some of the critics' comments on this series, and one that comes up frequently is that this is "Buffy lite." Not true. Butcher has created a different world than the one that Buffy inhabits, and this world is very well portrayed: the writing is excellent, the characters are well cast, and the production values are, while not exactly Peter Jackson quality, perfectly adequate to tell the story.
All in all, good stuff.