Ursula LeGuinn. Sci fi/fantasy writer who avoids the usual crap cliches and writes compelling and humanly interesting stories.
Philip K. Dick, Read Radio Free Albemuth, it's brilliant sci fi with lots of ingeious and mad ideas. It was his last book before he died, wasting away on a diet of stimulants (amphetamines, like Kerouac) that he used to help hiim meet deadlines, including, ultimately, his own. Do Androids Dream of Electric Sheep became the basis for the film bladerunner. The Minority Report became the basis for the same titled film with Tom Cruise. I haven't seen the film but the short story is in a compilation called "The days of Perky Pat" and is possibly the best short story I've ever read.
I've just finished reading an hilarious book called "The Quantity Theory of Insanity" by Will Self. It's damn funny and examines a very odd concept and its influence on other wise disperate lives of various people.
Margaret Atwood's "The Handmaiden" is a brilliantly written distopian novel. I haven't read any of her other stuff but she has a great reputation.
William Golding is often hailed as "the greatest living writer" and certainly books like the Inheritors, Lord of the flies, freefall etc are superb.
I loved Lloyd Alexander's Black Cauldron series,
I'm sure there must be others but these are the only ones that spring to mind at the moment.