Cassette Tapes
Ah, tape. Chewed up in school buses. Those were the days. Unfortunately, tape is showing it's age.
Poor quality playback (no bass slam or sound staging) compared to a CD. deterates after a couple of years- rewind/fastward is a pain.
Minidisc is replacing it. You still get people buying tapes- they haven't upgraded to CD yet!!
Walkmans are available for a tenner, so I think tape will be around for the next couple of years. Personal Minidisc players are still too expensive. CD Discmans are cheap now. Another tape format was 8-track. It could hold on the tape four stereo tracks, or different languages, or switchable story board for children's toys ( I had a one!)