An editor should be a writer’s best friend. A good editor can take a decent story and help the writer make it a very good, or even great, one. I’ve had the opportunity to work with several editors that I respect highly, but the one I probably enjoy working with most is John Joseph Adams at Lightspeed Magazine. (It has nothing to do his buying of several of my stories, either) Everything Mr. Adams does demonstrates his respect for writers, from the rapid review of his slush pile (1-2 days!) to his handling of editorial revisions.
Case in point, I received the proof for my story “The Schrödinger War” earlier this week, and it was filled with the typical line edits, but also with numerous suggestions where Mr. Adams felt the story could be strengthened. He exerted no pressure to make the changes if I didn’t want to; he only tossed them out there for my consideration. They’re good suggestions, and I’ll surely incorporate some of them (but likely not all) into the final version, resulting in a that story will be stronger for it.
This isn’t an isolated incident either. I went through several back-and-forths with Mr. Adams for “Thief of Futures” and a few for “Dreams in Dust.” Both stories, but especially “Thief of Futures” emerged better from the exchange. He does the same with other writers, too: author Jake Kerr has discussed the editorial revision process he and Mr. Adams went through for his story “Requiem in the Key of Prose.”
Mr. Adams has been nominated several times for the Nebula and Hugo Awards for his work at Lightspeed Magazine, but he’s yet to win either. If he continues to work with writers as he currently does, I imagine it’s only a matter of time before he’s recognized with some hardware.
D. Thomas Minton 
I often can’t help but pity editors; they take flack from writers, publishers, *and* readers. I’ve heard of several instances where writers verbally attack their editor because they’re, well, editing. So, kudos to you for not only acknowledging a good editor, but being the kind of writer who is open to editing of your work.
Thanks for stopping by. I believe all writers need editors (well, good editors), whether we think we do or not. I’ve seen many writers get “big” enough that they think they don’t need them anymore, only to produce bloated, self-indulgent work. None of my stories is ever perfect; a good editor can help me make it better.
Having access to a knowledgeable resource is invaluable. For me, it’s the big-picture advice. My prose is pretty tight on a line-by-line basis, but I need that second opinion who is willing to say, “This passage is dull,” or, “The pace flags here.” I want to know when an ending is unsatisfying or the payoff is not equal to the build-up. As I said in my last comment, if I recall correctly, I decided to rewrite an entire novelette based on a professional suggestion.
JJA helped me improved the endings of both “Thief of Futures” and “Dreams in Dust.” The endings were close, but his suggestions simply made them better. Endings are hard, so if you find someone who can diagnose a weak ending, they’re worth their weight in gold, IMO.