Short story word counts—how long should a story be?

In my new review of Strange Horizons fiction for The Fix, I wander aimlessly through the intellectual wilderness while asking how long short stories should be. As most writers and readers already know, there are many different types of short stories, including flash fiction, novelettes, and novellas. But what's the breakdown of these story categories by word count, and how long should a particular story actually be? I reveal all in the review—or perhaps I don't. How's that for being coy?

I should also add that in the review, I gush all over the story “Nine Sundays in a Row” by Kris Dikeman. I strongly suggest lovers of trickster fantasies check out this wonderful tale.