I prefer a more genteel approach than hurling footwear.
RAID is meant for uptime, not backup in the traditional sense. It provides no protection against fire, theft, a power short taking out your drives/system, virus, etc. And if most of your media is really from "alternative" sources, maybe you don't particularly care if you lose it. You could just collect it again. Or for stuff you ripped yourself, you could use the original media as your backup. I keep my CD collection around partly for that reason.
For backup, you need to honestly ask yourself how much of that data is critical to keep vs. good-to-have. The critical data I need would fit on one DVD (personal information, family pictures, etc.). The rest of it I already have on install disks or I can easily download again (web browser, email client, various utilities). And I keep a second copy, on an external HDD, of stuff recorded off my DVR, as it'd be a hassle to record it again. Still, that drive is only 500 GB total, with space to spare. It's not a practical option for 100TB of media.
Also, if you're going the RAID route, especially with that many drives, you have to carefully choose which particular flavor of RAID (and thus, what hardware) you get.
I'll let others with more experience chime in on how to pick a RAID setup, as it's not my area of expertise.