FullSync 0.9.1
FullSync is an excellent program for synchronization and backing up of important files. Most people will find it most useful to use it to backup essentials on a USB drive, but I also use it to sync any development projects across different computers.
It's very flexible, with great features. Fullsync allows users to choose which files to update (through simple clicking or advanced regular expression filtering), supports scheduled backups, and even handles backups over networking with a variety of protocols (ftp, sftp, samba).
I've never had a problem with FullSync, it runs extremely stable and fast. Highly recommended.
Official Site:
http://fullsync.sourceforge.net