So if Jim Butcher and Charlaine Harris got busy while Joss Whedon watched, the baby would be Dylan Dog. Dylan Dog is a Private Investigator that used to specialize in the super natural before a tragedy made him give it up and go back to the regular world. He's got smart-ass comments in life threatening situations, a comedic side-kick and, as per usual, there's the beautiful female client that walks into his office that ends up being the love interest. It wouldn't be a PI movie, supernatural or not, if there wasn't the damsel in distress that was more then meets the eye. Did I mention that it takes place in New Orleans? Of course it does, it's got supernatural things in it, where else are they going to live other then New Orleans.
I'm a huge fan of vampire, werewolf, zombie, and other supernatural themed movies, and this one had them all. Over all, I would absolutely recommend this flick. It's not terribly serious or scary, but it is a fun time that has a nice take on the whole supernatural world. Honestly, I'm kind of hoping that it'll have some sequels. With these kinds of movies it's really easy to set up for it. The fact that they didn't limit themselves to just werewolves, vampires or zombies you can go a lot of different directions or even ad in new subsets of monsters. Seriously, you should buy this movie!
UPDATE: Apparently it's based off a comic book, so I must find it!