My Best List for SF would be:
The Doomsday Book by Connie Willis -- really gripping, gut-wrenching, heart-tearing time travel novel set during the time of the Black Plague. Probably my favorite book ever. All of Connie Willis' books are great (except Passages, blah)
Memories by Mike McQuay - another time travel novel, but a bit different method to it -- the characters hop around through time. Lovely characterization for characters that I initially hated, then grew to love.
Canticle for Leibowitz by Walter Miller -- post-apocalyptic SF
The Sparrow -- Jesuits in Space!!! Another gut-wrenching book.
Eternity Road by Jack McDevitt -- another post-apocalyptic novel, but set long after the events. My favorite McDevitt book.
The Diamond Age by Neal Stephenson -- sort of cyberpunkish, kinda. Love this book. My favorite by him.
Neuromancer - the only book by William Gibson I love without qualification
The Anubis Gates by Tim Powers -- another time traveling fantastical book. Amazing, amazing!