That's a good plan, but you're planning on keeping that data on-line with regular backups. This means that you're regularly accessing the media (because it's online or near-line). I do something similar -- the data's on a NAS box (RAID0, so no redundancy), with monthly backup to external HDD. The external drives are rotated; the "father" and "grandfather" sets are in my drawer here at work.

Cris is talking about a different problem -- offline archival where he doesn't keep the original data online. I'd be really nervous about discovering in 5 years time that my data's toast. Regularly reading (and re-writing) it would make me much happier. Of course, if your data's not actually "worth" anything, then it's not such a problem.