I still use 3.5" floppies -- plenty of room for text files and spreadsheets. And they're a pain in the butt for someone looking for unauthorized access.
I still use audio cassettes -- the quickest way to record audio "on the fly." I use them for audio note-taking, not "hi-fi" applications.
I have a couple of minidisc recorders -- I'd still be using them if Sony hadn't designed them to be intentionally frustrating.
We used our video recorder (VHS, not Betamax) just last week -- my daughter was nostalgic for some old videos.