NASA, for example, has data on tape which requires machines that are no longer manufactured and are no longer available. NASA has a couple of these vintage machines, but given the amount of tape they'd need to transfer to another medium to save it, the machines would wear out before all of the tape could be run through them. So the tapes and the data just sit there, inaccessible. In any event, you're going to be transferring this data to another medium five years from now. Whatever hardware you use, automate the backup process as much as possible.
Automation is the key to all backup strategies.
Zips are floppies, for all intents and purposes, not reliable enough for longterm backup. And Jaz drives are just unreliable, flat out. I'd suggest MOs, like the Fujitsu. For long-term archival storage, rewritable CDs are the way to go. You can make an incremental copy to a rewritable CD, pop that in your regular CD-ROM drive, and make a copy.