I always do backups to an external hard drive. Have a 200GB 3.5" IDE drive in an IcyBox enclosure (which I got for free), plus a 160GB 2.5" drive in an enclosure that cost me £1. The drives themselves were £40 and £30 respectively.
I mean, damn, one terabyte. I could store my entire DVD collection on one.
You could also lose your entire DVD collection if one fails. I don't go in for stupidly big hard drives - too much potential for data loss.