Although I count Avram Davidson my genre fiction touchstone, people would be more than forgiven for considering me nothing but the cheap nonunion Indonesian gray-market ripoff of John M. Ford. He wrote (among many other things) alternate history horror mashups, Star Trek tie-in material, doggerel, RPG supplements, spy stuff about Christopher Marlowe, urban fantasy set in Chicago, snarky posts on the Pyramid message boards, and roleplaying game reviews.1 Only his stuff, see, was really, really good. We even shared credit on GURPS Infinite Worlds, which mostly boiled down to me being smart enough not to change John M. Ford's writing.
I only met him once to my certain knowledge, at either Origins or GTS one year, and tried to avoid being a big idiot fanboy at him. In retrospect, I'm not sure that was the right call,2 but at the time, I thought I'd see him again, surely. I almost got to hang out with him at another GTS (and use Neil Gaiman's tickets to see Penn & Teller with him, which is kind of a geekgasm of Six Degrees there), but his health didn't allow the trip at the last minute. He emailed me once or twice of his own volition, at which I was awfully chuffed, and he was nice enough to write the foreword (in dog-Kiplingese) to Suppressed Transmissions 2.
I'll miss the rest of John M. Ford's writing, and I'll forever miss the chances I didn't know I missed, to work with him or talk with him or just be a big idiot fanboy.
 For Isaac Asimov's Science Fiction Magazine. One hesitates to say that John M. Ford made me a roleplaying gamer -- but his reviews sure didn't slow the process down any. It sounded so fun!
 By contrast, when Poul Anderson died, I was kind of shamefully glad I'd been a big idiot fanboy to him the sole time I met him. After all, what else do I really have to say to Poul Anderson or JMF except something like "I totally love your stuff, pretty much without exception, and I have ever since I figured out how to read an adjective." And it's not like writers don't like hearing that.