If you like the cyberpunk, a not-so-well-known series is by Wilhelmina Baird
Crashcourse/Clipjoint/Psykosis
It runs out of steam a little towards the end of the series, and it does have a few annoying bits, but it's got a damn cool world and (mostly) interesting characters.
Another not-so-well-known far-future series that has some pretty cool (imho) ideas:
John C Wright's The Golden Oecumene -
The Golden Age (2002)
The Phoenix Exultant (2003)
The Golden Transcendence (2003)
C J Cherryh - I really enjoyed every one of her books, the way she did characterization and dialogue just hit the right spot with me, really immersive. Best non-fantasy series were
The Company Wars universe, from Downbelow Station to Finity's End
Cyteen - clone of a murdered top scientist/politician growing up (better than I made it sound)
Chanur - trader who gets caught up in economic and political maneuvers between species/empires.
Faded Sun: Kesrith
even the Foreigner series was mostly pretty darn good.
http://en.wikipedia.org/wiki/C._J._Cherryh_bibliographyOldschool - Anything by Cordwainer Smith is a jewel.
Other space opera/military/cyberpunk authors I liked, check out their various series:
Ken MacLeod - various series w/some great space opera, can't think of one I didn't like
Walter Jon Williams - some cyberpunk stuff, some space opera
Greg Bear - some really good space operas, especially Forge of God and Eon series
Larry Niven - Mote in God's Eye and a bunch of military scifi
Poul Anderson - a bunch of classics, the Flandry and van Rijn series are really good space opera
Richard Morgan - Altered Carbon series is awesome cyberpunk.
John Ringo - good military scifi
John Scalzi - ditto
EE "Doc" Smith - Lensman and Skylark series, just kickass old-school space opera, classics that started it all and still hold up decently well.
Rudy Rucker had some pretty good cyberpunk novels
Elizabeth Moon as mentioned, really good military/political scifi, some of my favorite series.