Mmm.. for this amount of data, I would use a couple of RAID1 arrays, with 2-3 8GB USB keys in each array. And maybe a couple of duplicate DVD-DL discs as well.

For my own stuff here, a rapidly expanding collection of 140GB of photos and stuff, it's simply kept on a hard disk, with a full backup on a removeable hard disc.

Somewhat worrisomel, that, but nobody has put the effort into making a better backup media for the modern age yet.

Cheers