“The Way of Cross and Dragon” - George R. R. Martin
“Shark” - Ed Bryant
“The Long Years” - Ray Bradbury
One of my favourites is fairly recent: “Echoes” by Alan Brennert.
That wasn’t there when I checked. 
Since the zombie lives… I like Sturgeon’s “Affair with a Green Monkey” a story from 1958 in which gay culture is integral to the plot. I haven’t read it in 20 years, but the last time I did it held up well.
R. A. Lafferty’s “Continued On Next Rock” is more fantasy than SF, but I’m not picky. Nominated for the Nebula.
I have good memories or “Inconstant Moon”, “Cold Equations”, “Screwfly Solution”, “Light of Other Days”, and others previously mentioned.
Probably not surprisingly, two of Asimov’s are my favorites: “Nightfall” and “The Dead Past,” with “The Nine Billion Names of God” also high on the list.
I’ve been out of the habit of reading for a while, now, and I think I’m going to enjoy tracking down some of the stories posted in this thread.
A similar question was answered for computers. If you have a fixed amount of money, and a difficult problem where the program will take many years to run, how can you most quickly solve it? Do you buy a computer now and start it, or wait to buy, and how long should you wait? With Moore’s law, computers double in capability roughly every 18 months. The answer there, taking into account Moore’s law, was that to solve your problem the fastest, you’d wait until your problem could be solved in 18 months to buy the computers and start the program.
From that, I’d guess that you’d want to determine the corresponding “Moore’s Law” for space travel, and send your ship when it will take one doubling time to reach the destination.[/hijack]
I’ll take a stab at why not (now that I’ve had a little time to think about it :)). Because there’s only one scientific advance, and it’s only used on a single human.
Readily recognizable science fiction typically has multiple scientific advances all over the place: Look at Star Wars, Star Trek, much of the work of the classic Science Fiction authors.
You may have a hard-and-fast rule that it only takes one single scientific advance, but people who don’t generally read science fiction may have different rules, even if they can’t readily articulate them.
I don’t personally care if it’s called Science Fiction or not, because everything is a continuum. No matter what your criteria are (if you can even get people to agree), there are always going to be boundary cases. This is definitely Sci-Fi, that definitely isn’t, and people will always argue over stuff in the middle.
Actually, science fiction writers tend to use as a rule of thumb that a short work should only feature a single major scientific premise (exceptions can be made for extremely widespread premises like space travel). Too much more than that, and you end up tripping over explaining all of your premises, and not have any time for the actual story.
From context, you probably mean the Clarke and Baxter novel “The Light of Other Days” and not the Bob Shaw short story “The Light of Other Days”
For Sale
Baby Rocket Pack
Never worn.
Indeed, most of the stories listed in this thread can be summarized in a couple of sentences because they involve only one unusual premise:
[ul]
[li]There’s a planet that experiences night only once in a thousand years.[/li][li]Someone invents a device that can view any event in the past.[/li][li]Bicycles have an interesting lifecycle[/li][li]A ship on a vital mission has a stowaway that will prevent the mission from being accomplished.[/li][li]A medical treatment vastly increases the intelligence of a previously handicapped man.[/li][li]A series of computers is asked about how entropy can be reversed.[/li][li]A device from the future falls into the hands of children from the present.[/li][/ul]
Even in Star Trek, each episode generally only adds one element to the basic “Star Trek” concept, so that many episodes can be described as “The usual Enterprise gang”[ul]
[li]encounters superior beings who test them[/li][li]travels to Earth’s past[/li][li]encounters a deadly weapon from a destroyed civilization[/li][li]etc.[/li][/ul]
P.S. There are a number of short stories that use the same kind of device that’s invented in the Clarke/Baxter novel.
See “That Only A Mother” by Judith Merrill That Only a Mother - Wikipedia
“Billenium” by J.G. Ballard.
People who write science fiction, people who write science fiction criticism, and people who’ve read a lot of science fiction for more than about a decade or so do generally agree that a story with just one scientific innovation is indeed science fiction, and they frequently agree that a science fiction story is often better for having only one innovation in it. If there are other people who think that a single innovation doesn’t qualify a story as being science fiction, they are ignoring the established definition in the field. Now, it’s possible that more recently there are people who want to change the established definition, and it should be understood that definitions do often get changed in that way. However, let’s be clear that what they are doing is changing the established definition and not using the term in the way it’s been used before.
Actually, perhaps there is one sort of story where there is just one scientific innovation which according to some people isn’t science fiction. That’s technothrillers:
Technothrillers are near future stories where the innovation is usually something with military or espionage connections. The story feels more like a spy novel, a thriller, or a novel about the military than it does like a science fiction novel. It’s almost never labeled as a science fiction novel on its cover or put in science fiction sections in book stores.
In any case, let’s be clear about something. Nobody in the science fiction community thought that “Flowers for Algernon” was anything except science fiction when it was published. It was published in a science fiction magazine, it was then anthologized in science fiction anthologies, and it won science fiction awards. Nobody in the science fiction community has ever claimed that it doesn’t fit in the genre. If someone tries to say that it isn’t science fiction, they are adopting a new definition of the genre. Again, it may be true that some people are adopting such a definition, but you should realize that it is a new definition:
There’s a PDF available here.
In addition, technothrillers generally treat the innovation as a prize to be captured or threat to be suppressed; the people in the story are usually not affected by the innovation itself, but are instead affected by the actions of the people who are seeking the prize (or seeking to suppress it). If “Flowers for Algernon” had been about people chasing Charlie Gordon to get the treatment or to kill him so that the treatment would be lost forever (no one in technothrillers makes backups), it would be a technothriller.
The Janitor on Mars.
What hurts most is that he’s not even a science fiction writer.
For what it’s worth, the Internet Speculative Fiction Database considers him a science fiction writer and that story a science fiction story:
He’s not primarily an SF writer, but he does sometimes touch upon SF themes.
That short story was the best SF I’ve read to date so I had to put it here as an option.