[DoctorSpooge]

Morgan's Takeshi Kovacs novels. Just forum search the name -- the series (I guess you could call it a trilogy) is mentioned frequently here.

Dan Simmons has a lesser-known hard-boiled noir series, the first of which being Hardcase. Joe Kurtz, the protag, is one bad motherfucker. And Simmons is a hell of a writer. IIRC it's out of print, so hit up a used bookstore.

Matthew W. Stover's Heroes Die + sequel for a brutal, pulpy (albeit well-done) science fantasy. Has some of the more brutal fighting you'll encounter, and Caine is certainly not a friendly guy.

Alfred Bester's The Stars My Destination -- well, I haven't read this in a long time, but it's 1) an absolute classic in the SF genre, and 2) the protagonist is a rapist. So again, not a friendly guy.

Because no one knows who the fuck he is, I'll pimp Peter Watts. His first trilogy (beginning w/ Starfish) doesn't really have any renegade male protagonist -- it's a female, and she's completely fucked up. As is everyone else in his novels. The first book, imo, isn't incredible, paranoia factor and sheer grittiness notwithstanding. The second, Maelstrom, is jam-packed with completely badass ideas in the hard science fiction vein.

edit: yeah, Karsa certainly qualifies as well. And everyone loves that series except for me. So you should give it a shot.