Some of my favorite books (and the categories they would fit into) are the following:
The Vorkosigan Saga, by Lois McMaster Bujold (Can start with either Shards of Honor, 1986 or The Warrior's Apprentice, 1986)
Military SF
Space Opera
Work set in a human interstellar empire
And later books in the series (Barrayar, which is the direct sequel to Shards of Honor, and The Vor Game, which is the direct sequel to The Warrior's Apprentice, and Mirror Dance, which is around 6 or 7 novels in) have won Hugos; Barrayar and Mirror Dance both won the Locus Award as well; and a related book (that takes place several hundred years prior) called Falling Free has won the Nebula. It could also be read for the challenge, as it's a stand-alone, but I don't think it's quite as good as the Vorkosigan novels proper.)
The Faded Sun Trilogy, by C.J. Cherryh (the individual novels are Kesrith (1978), Shon'Jir (1978), and Kutath (1979), but the only version in print currently is the omnibus The Faded Sun)
Soft or Social SF
Work with non-human viewpoint character for at least 50% of the text
Work with a third-person limited, multi-perspective viewpoint
Work set in a human interstellar empire
Work set on a space ship (non-generation ship) -- at least Shon'Jir is completely on a space ship and big chunks of Kesrith and Kutath are on the ship as well.
The Doomsday Book, by Connie Willis
Time Travel
Work with a third-person limited, multi-perspective viewpoint
Work that has won the Hugo Award
Work that has won the Nebula Award
Work that has won the Locus Award
Work published in 1993
The True Game series, by Sheri S. Tepper (starting with King's Blood Four)
Soft or Social SF
SF Masquerading as Fantasy
Male first-person narrator
Work set on a single human planet that is not Earth
Work published in 1983-1984
The Darkover Series, by Marion Zimmer Bradley (pick whichever seems most interesting -- my faves are The Forbidden Tower, Hawkmistress!, and Thendara House)
Soft or Social SF
Superhuman
SF Masquerading as Fantasy
Work set on a single human planet that is not Earth
Third-Person Omniscient (I think, for most of them, definitely for The Forbidden Tower)
Revelation Space, by Alastair Reynolds
Hard SF
Work with a third-person limited multi-perspective viewpoint
Work set in a human interstellar empire
Work set on a space ship (non-generation ship)
Soldier, Ask Not, by Gordon R. Dickson (or any of the Childe Cycle novels, but they're mostly stand-alones and I think this is the best)
Soft or Social SF
Military SF
Male, first-person narrator
Work set in a human interstellar empire
Work published in 1967
My Petition for More Space, by John Hersey
Soft or Social SF
Male, first-person narrator (I think -- pretty sure, judging from the title, but I haven't read it in years)
Work set on Earth with no space travel
Work published in 1974
