Saved by Dropbox
I have installed Dropbox on my laptops and my phone. On my laptops I use it for two purposes: synchronization and backup. Initially, I used it for synchronization of my private and my work laptop (both computers are running Linux).
The laptop at work is a bit unstable. It crashes probably 3-4 times a week, and I believe it has something to do with the temperature of the processor. It happened to me the other way, and an OpenOffice document was left in a state where the file did not contain anything else that zeroes.
Luckily, Dropbox keeps track on my revisions of the files. That means that I was able to go one revision back and recover much of my file (probably lost half a page). Needless to say, I'm pretty happy with the Dropbox service now!