So, I can't actually pick one, or even rank ten, but by decade (when they made the works most important to me) it's down to a short list:
- 1830s: Edgar Allen Poe
- … long empty stretch …
- 1890s: H.G. Wells
- … shorter empty stretch …
- 1930s: H.P. Lovecraft
- 1940s: A.E. Van Vogt
- 1950s: H. Beam Piper, Clifford Simak
- 1960s: Brian Aldiss, Robert A. Heinlein, Zenna Henderson, Frank Herbert, Andre Norton
- 1970s: Marion Zimmer Bradley, Katherine Kurtz, Fritz Leiber, Anne McCaffrey, Michael Moorcock, "James Tiptree, Jr", Roger Zelazny
- 1980s: Mary Gentle, William Gibson, Elizabeth Moon, Rudy Rucker, John Shirley, Bruce Sterling, Walter Jon Williams
- 1990s: Pat Cadigan, Greg Egan, Neal Stephenson
- 2000s: Neal Asher, Peter F. Hamilton, Alastair Reynolds
- 2010s: Mira Grant (aka Seanan McGuire), Martha Wells
I can make an argument for almost any of them to be "my favorite" depending on mood, but Piper might be the winner in a bracket contest. I suspect I'd get down to something like Piper vs. Egan and my head would explode trying to compare Space Viking with Diaspora.
My first pass at this, there were only 3 female authors (Pat Cadigan, Mira Grant, and Martha Wells). Several were only fantasy: Which I think less of, but I do read—and Leiber and Moorcock's science fiction are not their best works.
Many only had a few great books or short stories surrounded by a giant midlist of dullness, but that's also why Niven, Pournelle, Steven Barnes, Iain M. Banks, Dan Simmons, and Poul Anderson never made it. Several I do list produced dullness after their peak, like Gibson objectively only wrote one short story collection & 2 thin novels worth reading, one should not read McCaffrey's post-trilogy extended sequels, and anything Stephenson wrote after The Diamond Age needed an aggressive editor to cut out about 2/3 of his text. And yet many continue to write exactly what I like, decades later.
The '60s-'80s really produced a LOT of SF I liked. Was it objectively better? Or was it just "the golden age of SF is 12" which was 1982, so I read what was still in print?