I'm not a big fan of crime fiction, but I finally got round to reading Patricia Cornwell's Scarpetta series and loved it (as far as the change to third person narrative, at least). I'm now demolishing Kathy Reichs' Temperance Brennan (Bones) series with similar relish.
I think it's the forensics / procedural combination that clicks for me - probably helped by a first person narrative style and (possibly) a female lead character.
I'd appreciate suggestions as to where I go next.