Of course it's Robert E. Howard. The single strongest contestant in all of Appendix N was the author of "Conan," "Solomon Kane," and dozens of other adventure stories. Jack Vance put up a fight but still trailed Howard by 50 votes at noon on April 1.
I think that running the tournament specifically related to "Appendix N" was what gave Howard the edge. The famous Appendix, of course, is the inspirational material for AD&D - and there is no purer source of the game than those original Conan stories. Conan can be a fighter or a thief, but he is what so many PCs aim to be. Howard's Hyborian Age is the kind of gritty, reference-but-don't-copy kind of place that many D&D adventures are set, and let's be honest: most Neutral PCs pretty much act with Conan style morality.
The Texan was the father of sword & sorcery, and a successful author in several other genres. He was compelling in crafting an adventure tale and had a knack for the kind of vivid prose that pulp fiction thrived on. It was a deep shame that he died when he did; had he lived several more decades he might have created wonders we can only dream of.
I'd like to thank everyone who voted and discussed all the authors in this project. A month is a long time to stick with something, but it was tremendous fun to discuss authors that are very dear to me (and clearly to some other fans). I learned a tremendous amount, and did a lot of reading to catch up; I hope if nothing else this inspires D&D fans to discover some of the tremendous authors out there.
And I'll leave you with the following, from "The Phoenix on the Sword":
What do I know of cultured ways, the gilt, the craft and the lie?
I, who was born in a naked land and bred in the open sky.
The subtle tongue, the sophist guile, they fail when the broadswords sing;
Rush in and die, dogs—I was a man before I was a king.