Zetabyte's Zbox isn't just a networked storage device. Every bit you put on the drive gets uploaded to Amazon's S3 storage cloud. So, if an earthquake, tornado, flood, or any other natural or unnatural disaster takes out your pad, your stuff is safe and sound over at Amazon's batcave. The hardware doesn't cost anything. Come again?
Ya, that's because you'll be paying about a buck per gigabyte every month for the privilege of online data mirroring. It costs $50 for 30 GB, and plans scale to about $300 for 690GB. The boxes themselves run power PC processors, have 128 MB of RAM, and check for software updates every hour.
This is basically better than any backup drive you can find...as long as you can afford it.