It's odd. I saw the series first. Took me a while, too - I couldn't get past the title, "The Dresden Files." My brain kept telling me it was a series about war. Either that, or an American series set in Germany which seemed just strange.
I finally got round to watching it, and I, too, was underwhelmed. I like to give things a chance, watch a few episodes before making a judgement. Well, I watched the whole 12 episodes of this and was still underwhelmed. Well, that's not quite true - I finished the series feeling very sad that I wouldn't be seeing Murphy or Bob or the various members of the supporting cast again just when it was finding its feet.
Then I read the books - I was cautious and only got the first two to give them a chance. A few days later I bought another one. The following day I bought all the other ones I could lay my hands on! I think it's fair to say that I LOVE the books. And you know something? Reading the books has made my appreciation for the series grow. I know that they're completely different kettles of fish - blonde / brunette; skull / ghost; diplomatically challenged loyal, faithful wizard / smooth, sophisticated (well, relatively), promiscuous (see previous parenthesis) hocky player. Somehow, though, the love of the books has smoothed over my annoyances with the TV show 'til now I can take each on its own merits. (Except Paul Blackthorne, who's still a bit dull phlegmatic.)