Actually, I'm one of the Admins over at a
Science Fiction Message Board where we discuss this type of stuff every day.
My personal favorites include Alistair Reynolds, Stanislaw Lem, C. J. Cherryh (she does fantasy too, but her science fiction is quite good),
David Brin,
Kathleen Ann Goonan, Octavia Butler, Ian McDonald,
Michael Moorcock, H.P. Lovecraft, Jack Vance, Greg Bear, J. G. Ballard, Barry Malzberg, Ursula K Le Guin, Samuel Delany.
I'm currently reading the latest Foreigner series book by C. J. Cherry, called, awkwardly, Deliverer. I like her Alliance/Union universe better than this one though.