Stephen King is one of my favourite authors (although he has released some absolutely crappy books alongside with his gems, heh) and used to be number one. The Dark Tower is best "epoch" ever, even beating LotR
In my opinion best speculative fiction author (and one of the best authors overall, not just in the genre) is Le Guin. She's just marvelous.
Hmh, I guess my top three would be Le Guin, King and Martin
It should be noted however, that - srangely enough - I rank works from such directors/auteurs like Hayao Miyazaki, Akira Kurosawa, Coppola, Shion Sono and, of course, especially Hideaki Anno above many of the greatest classics/books in history of literature. (Don't ask why that quick list has so many japs - I guess it was because first one to come in my mind was Anno, which led me to think other great japanese directors)
When it comes to music, Beethoven's 9th Symphony is also one of the pieces I'd rank above any book I've read. And I've read many books.
It's strange, I've done writing for a long, long time yet most of the works on my greatest works of human mind list aren't books. (for example, I still hold view how Anno handles/represents human psyche and subconscious in NGE is by far superior to even how Dostojevski does it. Of course, some of that superiority comes from natural edge of animation over text when dealing with such concepts) I'm not saying there aren't ones, but they're minority
Hmh.
edit: Almost forgot!
is something entirely "different" yet fantastic!
...I wonder why I rank many animations so high, considering how crappy I'm at drawing