Lawrence Block, Michael Connelly and I'll toss in Stephen Greenleaf as my current favorites.
Those are the ones I've cared enough to reread. Ray Bradbury also wrote a great mystery if you haven't read it - "Death is a Lonely Business"
I also like R.D. Wingfield, Charles Todd, James Lee Burke, the Kellermans, Dennis Lehane and Reginald Hill though I don't feel any inclination to reread them. And I haven't read them in a while but I used to love Robert Barnard "Death of a Mystery Writer", Eric Ambler "A Coffin for Dimitrios" (kinda spy/mystery story though), A. Conan Doyle and Dorothy Sayers. I read those back before I found fantasy and then science fiction.