POLL: Your Top 10 Science Fiction Authors of All Time!

[Shelby]

I've been inspired to conduct a poll and see who my friends might consider the “Top 10” science fiction authors.
Use a broader definition of the “science fiction” genre, one more in line with what you might find in the pulps. IE, don't automatically exclude someone who might be termed a “fantasy” writer.
Not just a matter of personal taste, but standing head and shoulders above any before or since.
Significant and visionary. Starting with a look at the Grand Masters is recommended.
It should be very difficult for more recent authors to displace some of the giants that have come before.
Nominate ten. Feel free to explain if a choice might seem controversial or out of place.
I'll total up votes for winners.
Go.

Examples for your consideration:
Poul Anderson
Asimov
Bradbury
Brin
Cherryh
Clarke
Philip K Dick
Ellison
Phil Farmer
Gaiman
Gibson
Heinlein
Herbert
Laumer
Tanith Lee
LeGuin
Lovecraft
Niven
Andre Norton
Pohl
Pournelle
Simak
Cordwainer Smith
Vance
Verne
Vonnegut
Wells
Zelazny

My Top 10:
Poul Anderson
Asimov
Bradbury
Clarke
Philip K Dick
Ellison
Heinlein
Herbert
LeGuin
Zelazny

Man, that's HARD!