OK, here we go:
by Keith Laumer -read the original, not the sequels by other authors. Although Road To Damascus
stands up really well
by Michael Z Williamson. Also, Freehold
by the same author.
A Talent For War, Seeker
- all by Jack McDevitt, about a guy who tracks and trades in antiques, only it all takes place a thousand+ years in the future so the stuff he deals in hasn't even been built yet in our time...
Orion Shall Rise
by Poul Anderson(and if you like it, the short story collection Mauri and Kith
details more about the Mauri Federation)
Most of H Beam Piper's work fits your request. So does Allen Steele's Nearspace novels(check wikipedia for a list)
The Mote In God's Eye
Santiago, A Myth of the Far Future
by Mike Resnick
another SM Stirling suggestion would be The Peshawar Lancers
One that may come close to hitting every point you mentioned is David's Sling
by Mark Steigler
and a couple of classics that fit would be Logan's Run
by William F. Nolan, The Stainless Steel Rat
by Harry Harrison, another vote for The Moon Is A Harsh Mistress
and Starship Troopers
, The Riverworld
series by Phillip Jose Farmer, and the Nine Princes In Amber
by Roger Zelazny.
There's also Dean Ing's novels, the original 3 Draka novels by Stirling(available in omnibus, I believe), the Retief books by Keith Laumer, and the Timeliner trilogy by Richard C. Meredith. Oh, and the Dorsai books by Gordon Dickinson as well as Pournelle's Falkenberg stories/novels. That should keep you busy for a few weeks.