The Dresden Files are a blast. I tore through them all in one week in Mexico last year (nothing like Montezuma's Revenge to keep you indoors and reading on vacation!)
Haven't read the last one yet. Waiting for the ebook-being-crappy thing to work out.
Going to give Preston a go. He wrote the book that the movie Relic was based on? I'll not hold that against him.
I also really enjoyed "The Alienist" if anyone has any recommendations along that vein.