Accidentally deleting or losing important files is incredibly frustrating, especially as it's so easily avoided. Although, as computers become more stable, the chances of such a situation occurring are lower than ever. However, backing up important files is essential, just in case the unlikely does happen. If disk space is a problem, you could always use and FTP server as a place to keep files and folders.
Comodo Backup is a free application that enables you to backup to another disk within your system, an optical disk or cloud storage. Backups can also be compressed or password protected and the application supports one-click backup of important items like email accounts.
Note you receive 10GB of free online storage using Comodo Backup, at the time of writing.