Well, since magnetic media has a very finite lifetime, you don't have much longer to worry about Zip disks -- they'll all be unreadable soon.

Which brings me to another fun story. My girlfriend runs a book conservation lab, and she was wondering if she should try to read the bits on a floppy disk associated with a book on numerical methods -- it costs $$ to try to read the disk, and given the age, it was unlikely to work. I know one of the book authors, so I told her I likely could probably find a copy of the software on the Internet, if she found some pages that listed the names of the software functions. Turned out that it was a copy of LAPACK, which is available at NETLIB. Only one checkin to the code since the book was published in 1986...

That thought literally (almost) keeps me up at night.