solution for archiving digital video
Your best bet is to save them on two disks, that is two back up copies. A RAID sounds nice, but have you ever had to replace a RAID system with a faulty controller? It can be a nightmare. Forget RAID as a back up unless you are talking about an instant snapshot retrieval system that is online 24/7. If you are talking about a long term back up as in a real archive then get two USB disks with enough capacity and make two copies, one on each disk.

Tapes will require hardware that may not be around when you want to retrieve the data.

As a systems administrator for many years please allow me to demonstrate this issue.

In the 1980s we used 1/2 inch tape transports to back up our servers, this was replaced by 8mm tapes by 1995, 8mm tapes were replaced by DLT transports, DLT was then replaced by super DLT, which then was replaced by LTO. This never ends. If you wanted to read those old 1/2 inch tapes you would have to go to a museum, and this will eventually be true for every tape transport system that was ever developed.

Yes disk interfaces change, but getting a conversion interface say EIDE to USB, or ATA 100 to USB, or SATA to USB is easy. Other serial interface conversions will be easy too vs. trying to locate a 'vintage' tape system that still works.

I only shoot on digital memory, so backing up my data is simple and painless. I make two back ups on two different disks. The disks are then removed from service and stored where they will not get toasted, or frozen. I only use these disks when I need to update the backup. Eventually when they are full I store the disk in what I call a dormant back up.

Because I only power up the disks when I either need the data or I need to do a back up increases their reliability. Most disks have a 5 year warranty, if these are on 24/7 or turn them on every time I use my computer I would be needlessly heating them up, and after 50,000 hours they may not work. Using the back up disks only when you need them will extend their life way beyond 5 years.

Currently I have two 2 TB disks as my active back up. I have two 1TB disks in the dormant state too.

Like a volcano, information has 3 states: Active, Dormant, and Extinct.
Active data should be accessibly 24/7, dormant should be available, and extinct goes to the shredder.