Sleepless in a Marriott. Been meaning to write a version of this for a while.
I have been slowly saying goodbye to:
Tabletop role-playing games.
Floppy comic books.
Comic book shops that sell floppy comic books.
Print science fiction magazines.
Some of these will stagger on for years yet, dwindling but still around. In 2020 I expect Usenet will still exist, in some attenuated spam- and troll-infested form. And a decade later, when we're all driving hydrogen-powered cars and getting text messages from the AI sailing the blimp probe around Venus, there will still be a few retirement-age guys gathering to play D&D. (Or, more likely, to argue about which edition. "But 3.x nerfed the druid!").
Print SF magazines, on the other hand, are clearly circling the drain. They'll be gone within five years. And traditional floppy comics won't be far behind -- they locked themselves into the comic-shop market back in the 1980s, and a lot of comic shops are marginal businesses that won't survive the recession.
Print newspapers are the only thing on that list that's of much consequence or interest to the larger non-nerd world. Smart money says that within a year there will be a major US city, and probably several, without a daily paper. I don't think that's been true since... oh, the 1850s at least. It's a little hard to imagine America without newspapers and everything that goes with them: headlines, political cartoons, editorial endorsements, Sunday color funnies. Sic transit gloria mundi.
What will you miss?