I was considering this just recently. I've come to the opinion that much of what makes the book series good is the internal dialog (well, monologue, I guess) of the main character. That's not something that is frequently (or ever?) done well on screen. Representing the events of the books in normal third-person perspective would lose so much in the translation, that I'm not sure I'd want them to bother.
Ah Dresden Files.... I liked the show. I like the books.
Jim Butcher spoke at a book signing I was at about the "why it got canceled" and the core factors were:
SciFi sold the wrong ad slots for "men's stuff" when the demographic was 30-40 year old women that were watching it
And, the president of SciFi was jealous of the VP who sponsored Dresden Files and cut it to make room for Wrestling. Basically, the VP's shows were doing better than the president's. It sounds like they had some kind of show sponsorship thing, where different VP's etc sponsored shows that got made.