Vance, Zelazny and Wolfe have been listed, so I’ll offer Dan Simmons. He’s relatively new, but his best science fiction is perhaps the best science fiction ever written.
Lord of Light is his best, Creatures of Light and Darkness is the one you’ll enjoy the most, but like many listed here, his best stuff was his short stories. Look for any of the anthologies.
Oh, and avoid the *Amber *series. It’s highly overrated.