Here are some statistics that may provide suggestions for your votes for current and all-time best short fiction writers. Keep in mind that statistics such as these indicate how prolific a writer is as much as how popular a writer is, of course. You can vote for anyone, not just writers on this page.

Number of (short fiction) entries in the Index to Science Fiction Anthologies and Collections before 1984. (These are counts of total number of reprints, not of separate stories.)
433. Ray Bradbury
338. Isaac Asimov
255. Harlan Ellison
254. L. Sprague de Camp
238. Poul Anderson
218. Robert Bloch
202. Brian W. Aldiss
189. Robert Silverberg
186. Fritz Leiber
167. Barry N. Malzberg

Number of short fiction appearances in all Locus polls, 1971-1997 inclusive:
60. Robert Silverberg
37. Lucius Shepard
32. Michael Bishop
28. Gregory Benford, Connie Willis
27. Frederik Pohl
26. Ursula K. Le Guin, George R. R. Martin
24. Harlan Ellison, James Tiptree Jr.
23. Michael Swanwick
21. Nancy Kress
20. John Varley, Howard Waldrop
19. Gene Wolfe
18. Orson Scott Card
17. Greg Egan, James Patrick Kelly
16. Kate Wilhelm
15. Mike Resnick
14. Avram Davidson, Gardner Dozois

Number of short fiction appearances in Locus polls, 1990-1997 inclusive:
17. Greg Egan
13. Ursula K. Le Guin, Mike Resnick, Robert Silverberg, Connie Willis
12. Terry Bisson
11. Nancy Kress
9. Robert Reed, Lucius Shepard
8. Stephen Baxter, Pat Cadigan, James Patrick Kelly, Brian Stableford, Michael Swanwick
6. Joe Haldeman, Maureen F. McHugh, Charles Sheffield, Bruce Sterling, Gene Wolfe