So we've mentioned Zelazny a few times before, but I thought he warranted a category of his own.
I've read The Chronicles of Amber (all 10 of them) A new BIG edition with all of them came out not too long ago. One of the most creative worlds imagined. Zelazny is an action-adventure writer with a truly immense imagination. He's the proof a writer can dream up anything and make it work.
I've read his short story collection: The Last Defender of Camelot. A vampiric robot--brilliant.
What else would people recommend?