I have been shooting digitally for about six and a half years now. I've been shooting video for half that time. My digital archive is, in a word, daunting.
My main backup is to bare hard drives, often to older, lower capacity drives that I'm replacing in my main desktop and attached storage. That setup is now all now 2tb each (10 of them), in two MacGuru Burly Boxes and as internal data drives in the MacPro. I have a backup set of bare drives in the office, and a duplicate set that lives across the street at my mother-in-law's house.
Hard drives are a little like living beings. They need exercise. If you parked a hard drive on a shelf and plugged it in ten years from now, you'd have two problems. One, the hard drive connector has probably changed in that decade and you won't have a plug that fits. And two, the drive bearings and the lubricant will have probably congealed into a sticky, immobile mud and your drive will fail to spin.
So, every six months or so I bring the boxes of drives from across the street and plug them in. I run Disk Utility to verify the drives, and also run a short test in Smart Utility. I wasn't surprised that one drive (out of warranty) was on its way to the grave with a bunch of bad sectors. I ordered some new drives and will transfer the data when they come.
Wiebetech makes a great plastic case to store your bare drives. I archive the contents of the drives in a Media Pro catalog so that I can know what drive to grab if I need to get the data. I have an external eSata drive box, with the cover stripped off, that I use to read the access the drives (there are more convenient solutions where you plunk the drive headfirst into a slot, like the Thermaltake BlackX that I have. It's unreliable, however, and often fails to connect or keep the drive online).
With video I'm going through drives at a faster clip than my upgrade cycle, so I'm regularly buying new drives now. I buy only retail drives (the OEM drives from Newegg and the like aren't as reliable) through MacGurus.
Keep your data watered and fed. It will disappear if you don't.