I use double-protected cloud storage. I use a SkyDrive account folder on my computer, and I configured my Dropbox folder to be inside of that. That way, I can store my projects on Dropbox, and it will sync to their servers, but because the Dropbox is inside my Skydrive, it's synced to their servers at the same time. That way it's very unlikely that they're lost. And to my knowledge, Dropbox AND SkyDrive provide a file history, so that anything accidentally deleted can be recovered. Right now I have about 4GB of storage available on Dropbox, so until that runs out I'm happy using this method.
The only downside is that it limits where I can code, but it's not that bad. If i know there won't be internet access where I'm going, I'll only stick to one computer for coding and sync it up when i get back.