Installing CrashPlan on my QNAP TS-210 NAS in headless mode means that I have an instant online backup of all of my archive data stored on my NAS drive. CrashPlan keeps revision history of all my files, allowing me to recover my NAS to a state at any date should I lose data or overwrite something.
Use Dropbox Dropbox to get free cloud space to store important files, documents, photos, etc and be confident that they are automatically backed up on both your computer and securely on the internet. Install Dropbox on multiple PC's and have the files automatically sync'd between the two.
I use Dropbox to automatically sync my documents between my two computers. This works seamlessly and no sooner have I saved a document on one computer is it ready and updated on the other. Dropbox works faultlessly in all tests I have put it through, simply Excellent.