I use different types of backup for different types of data. I categorize my data into tiers one, two, and three.
Tier One
This is personal data that comes from me. i.e. Personal spreadsheets, writings, tax documents, etc.
This is also any personal pictures or original work.
If you’re anything like most people, you’ve got less then two gigs of this type of information. There’s plenty of online services that will sync your data seamlessly in the background. I might actually have a beta invite for dropbox if you’re interested. I’ll have to check when I get home.
Tier Two
These are movies, games or files that I’ve gotten via the internet or other means that are not easily replaced. This is obscure rips of B movies or mp3s of out of print records or important e-book manuals.
This type of data I back up to an external hard drive in case the original copy dies. It’s stuff I care about, but not enough to have another backup off-site.
Tier Three
These are general movies, music and games.
I don’t worry about backing this stuff up because if I loose it, I can get it again. It’s no big deal. Most of this stuff I haven’t really looked at in a while anyway.
My Setup
I also keep all of my data on a raid 5 file server on the network but that would be overboard for most home type situations. Raid 5 is great because one of the hard drives could die and it would rebuild itself if you replace it before another dies.