There's a fundamental problem with reading or writing sex stories: two separate and almost exclusive standards of quality. There's good writing and then there's wankable writing. One has effective characterization, a creative premise, lush sensual detail, and high technical standards. The other pushes the right buttons in rapid sequence with wild abandon. Good writing is something people can often agree upon; wankable writing depends on your individual buttons. And wankable writing generally can only be identified mid-wank; it turns to sand in your fingers (or incoherent rambling on your screen) at the moment of orgasm.
Printed "erotica" (I don't like that word, it's like they think they're better than plain ol' porn) anthologies tend to be nothing but good writing. Absolutely useless for wank. I'd rather read pages 936-944 of my anatomy textbook.
To be honest I almost never read good sex fiction. When my pants are zipped, I tend to realize that sex just isn't that rich a topic for a short story; there's really only so many variations on the ol' in-and-out, and the writing gets caught in an awkward spot where it's too committed to sex to work as full-fledged fiction. It's like reading about someone eating--I'm not getting bored of eating itself anytime soon, but do I really get much intellectual stimulation out of "once again he lifted the fork to his dripping piehole"?
What's really funny is that the things I enjoy reading about aren't entirely connected to what I enjoy in reality. I love being spanked and giving blowjobs, but they do nothing for me in writing. On the other hand I'm not that into the buttlove in reality, but it's practically a prerequisite for a story to pass the Left Hand Test.
So you can keep your Best American Erotica; I'll be on the Internet looking for the Most Frothingly Analcentric Probably-Not-American-Judging-By-The-Grammar Erotica.