Which of these do you remember using?
(For avoidance of argument, Sinclair Microdrives are magnetic tapes: 2" and 3" floppies are 3.5" floppies; Zip drives don't count (they're too modern))
@cstross I would add cassette because they are contemporary, but I never had the chance to use them myself. Tapes for backups do not count.
@mdione You clearly didn't read the poll.