That's my primary use case for Amazon Drive. I have a robust rsync of the workstations and laptops to a NAS, and then to a second (incremental-only, no delete) NAS. Works great, but if the house burns down, or if someone breaks in and steals the computers, I want to ensure there's a copy somewhere.
If that is your main concern you could always put it on an external drive and put it a bank safe deposit box. I've thought about doing that for at least the very important things, perhaps even printing some important pictures too.
A good scenario is building a backup server/nas solution that you can put in a little cubby at your friends place. There's trust involved that you're not using their internet to hack the government, and you have to be mindful of their bandwidth/power costs. So not a rackmount server or even a tower, but something much smaller and very appliance looking. A nuc sitting atop a wd passport or their "my book".
If it provides them a benefit like an in-house plex server, even better.