What is equally as important as the data itself is the system with which to read the data.

It's not much use having backups if you don't have hardware and software with which to read it.

Iomega's Zip disks were once the industry standard backup, for example. There are computer users nowadays who have never even heard of them! I have working Zip100, Zip250 and Zip750 drives - the Zip750 is capable of reading (but not writing) Zip100 and Zip250. Only recently I had to extract data from some old Zip100 cartridges for a friend which, luckily, were still intact.

IDE drives (PATA) were superceded by SATA drives, so a lot of modern computers cannot read them - unless you can lay your hands on a USB / PATA drive caddy... but how long will USB be around?

So migrating your data to the most current media type is wise, but only if you've software capable of making use of the data...

My preference is to use Network Attached Storage with mirrored drives, and to keep multiple copies on other media as well. I also keep old hardware which often comes in handy when people find they have old media but not the hardware to read it!