Top eight series/ top eight individual books in vague order:
Farseer/ Elderlings (The Golden Fool) - Robin Hobb
A Song of Ice and Fire (A Storm of Swords) - George R. R. Martin
The Chronicles of Thomas Covenant (The Power that Preserves) - Stephen Donaldson
The Book of the New Sun - Gene Wolfe
The Culture books (The Player of Games) - Iain M. Banks
Malazan Book of the Fallen (House of Chains) - Steven Erikson
Long Price Quartet (An Autumn War) - Daniel Abraham
The Gap series (Forbidden Knowledge) - Stephen Donaldson
Stars in My Pocket Like Grains of Sand - Samuel Delany
The Dispossessed - Ursula Le Guin
The Road - Cormac McCarthy
Dune - Frank Herbert
The Goblin Emperor - Katherine Addison
Inverted World - Christopher Priest
Speaker for the Dead - Orson Scott Card
The Scar - China Mieville
I've missed off some great authors - Neal Stephenson, Philip K. Dick, Lois McMaster Bujold, Dan Simmons, etc - as although their work is fab, I don't quite love any individual book enough. I've probably forgotten a few I might have listed, as well.
Stars in my Pocket Like Grains of Sand by Samuel R. Delany is by far my favorite sci-fi novel.
yup, it is totally amazing. It needs more love.