Just some of my favorite authors: George .R.R. Martin, Keith Laumer, Larry Niven, Tom Godwin, Louis McMaster Bujold, J. Gregory Keyes, Terry Pratchett, Eric Flint, David Weber, Anne McCaffrey, Christopher Anvil and Michael McCollum.
Some exeptionally good stuff from these authors:
Antares Trilogy from Michael McCollum
All Miles Vorkosigan books from Louis McMaster Bujold
The early Dragonriders of Pern Books from Anne McCaffrey
The Stars at War Megabooks from David Weber
Mostly anyting else from David Weber if you can stand the occasional 50 pages sociopolitical excurses.
The Mote in God's Eye and The Gripping Hand from Lary Niven
Night Watch and Thud! from Terry Pratchett
Oh, and i am back!