I use CrashPlan both personally and professionally as my backup choice.
CrashPlan will let you back up to a remote server, for a small fee, just like any other online backup software. What makes CrashPlan so unique, is that you can back up to your friends, or your other computers, for free, regardless if they’re on your LAN or not. You can back up to multiple sources as well. For example, a PC in house, and a friends PC across town. You have the convenience of a local restore being quick, and the security that your data is off-site in case of a disaster or theft. Oh, yes, your data is encrypted. No need to worry about others seeing financial and other private information.
For personal use. It’s free. Though a bit limited. You can upgrade to CrashPlan+ to make use of some great additional features, like data de-duplication, real-time backups, heavier encryption, and file versioning. However, if you want it for free, it’s still the best choice out there.