Oh, wow. Of
all time? Interesting thread. I would echo the sentiments of those on here who find it next to impossible to list a single favorite. I also don't think it's possible to combine genres and somehow come up with a best story out of all of them, since I tend to view different genres as trying to accomplish different things philosophically and artistically. This is a fun exercise, though! Narrowing it down as much as possible, and considering which stories I adore for specific personal reasons vs. which shine in a more general 'literary merit' sense, I've come up with the following, from some of my favorite authors:
Kobo Abe: "The Magic Chalk" (quoted in my signature!
)
I would say Kafka's
The Metamorphosis, but that's more novella-length and I'm pretty sure most translations are over 20K words.
Aimee Bender: "The Healer"
Donald Barthelme: "The Emerald"
Joseph Conrad: "The Secret Sharer"
Susan Steinberg: "to sit, unmoving" and "Superstar" are both good contenders, I think. The former was prize-winning for good reason.
When it comes to sci-fi, anything from Bruce Sterling's Shaper/Mechanist universe is absolutely stellar, particularly "Swarm" and "Twenty Evocations". Those stories were eons ahead of their time and made breathtaking existential points as well as any non-spec fiction.