I love mysteries that are definitely NOT cozy.  I love 'em with some grit and intelligence.  Here are a few of my favorites that I don't think are quite as mainstream as authors like Patterson or Michael Connelly:

John Connolly  (Charlie "Bird" Parker series)

Ken Bruen (Jack Taylor series)

Michael Harvey (The Chicago Way)

Adam Baron (SuperJack)

G M Ford  (Frank Corso series)

Harry Hunsicker (Lee Henry Oswald series)

Michael Koryta

Declan Hughes (Ed Loy Series)

Kris Nelscott (Smokey Dalton Series)

Wallace Stroby (Barbed Wire Kiss...could you find a better title???)

Dan Simmons (the Joe Kurtz books 1, 2 &3...Hardcase, Hard Freeze and Hard as Nails)

These are only a few of my favorites...anyone else like to pass on suggestions?

Robin

I am more of a science fiction guy...so maybe it shouldn't be any surprise that Isaac Asimov is my favorite mystery author.  His book A Whiff of Death is probably my favorite.  In fact I think I like it better than any of his SF, and it is definitely not a cozy :p

Carl Hiassen, Lawrence Block, Reginald Hill, Ian Rankin

Karin Slaughter - some of her characters and their crimes are so horrific sometimes it's hard to believe the author is a woman.  I love it!

Andrew Vachss

Joe R. Lansdale

John D. MacDonald

I'm reading The Color of Blood by Declan Hughes right now, and he's pretty hardboiled.

Oh gosh - don't get me started!!!  LOL  Let's see:

1.  Mary Willis Walker - hometown gal whose books are all set in Austin, TX

2.  David Wiltse

3.  Stephen White

4.  Jeffrey Deaver

5.  Greg Iles

6.  Alex Kava

7.  Chelsea Cain - Heart Sick and Sweetheart are FABULOUS

8.  Carroll O'Connell

9.  P. J. Tracy

10.  F. Paul Wilson

11.  Ridley Pearson

etc. etc. etc.

Dashiell Hammet

Mickey Spillane!

Would John Sanford count?  I just started his "Prey" series.

Lately I find myself drawn more toward the hard boilded and /or gritty types of mysteries.  I gave cozies a fair shot but they just don't hold my attention anymore.

John D McDonald, Raymond Chandler, and, of course, PJ Tracy!

How about trying a non-fiction mystery?  For instance, My Dark Places by James Ellroy.  He was 10 years old in 1958 when his mother was murdered, and in this book he describes how it affected his life by sending him on a very dark downward spiral.  He also chronicles  his  attempt, years and years later, to solve the mystery.  The book is very gritty and "noir", and might open you up to the true life genre.    (And it's on my bookshelf, if you're interested!)

I think T. Jefferson Parker is vastly under appreciated.  Really good writer.  John Sandford would definitely be in this class, esp. his early ones.

Otherwise mine have been mentioned. 

Oops, guess I'm not done .... I'd also add Jo Bannister, another English writer that gets very gritty and Lee Child, Jeff Abbott.  Nevada Barr can get pretty gritty but milder than these others--still excellent.