I sold all rights, so the story is theirs. Their pay was a nice three figures, and at the time I was selling regularly to three-figure markets, and had been for over a decade. I'm satisfied with the sale, with the money, so that isn't an issue.
Usually, if a magazine goes out of biz and hasn't been sold to another company and has no intention of starting up another mag, even if you've sold all rights, in most cases they will sell (or if you're really lucky, give), you back, your rights. You can always ask. If you have a story you strongly feel will sell to another market quickly and for the same or a higher price, it's probably worth offering to return their full payment when you ask.
At the time I sold the story, I didn't think the story could sell to another market, and certainly not for what they paid me. There was no internet then, so I had no webpage. The real reason I'd like to see about getting my rights back is because I'd like to post the short story on my webpage. I've got serious health problems and I'm not able to write in volume anymore. I can only submit to a few $20-and-under email markets per year since I can't afford print toner, paper, or postage. If I did get back my rights (and due to my financial circumstances I couldn't afford to buy them back) I may be able to have the short story published in some low paying mag after a not-worth-it marketing campaign.
It is not future earnings I care about. I like the story. It's one of my best. It showcases well the subject matter and style I enjoy writing in. I'd like to be able to feature it on my website. I seldom put nonpublished stories on my site unless I see no paying market for them; I don't want to lose the ability to sell first publication rights.
We all have our favorite stories, stories we know highlight our writing in the way we like, stories we're proud to have conceived. I'd just like to post the story to be able to say to those who surf to my site, "Hey, here's a short story you might enjoy reading.".
But, all in all, considering the money involved, the sale was still well worth it. At least financially.