CLEO is a perfect way to backup your Firefox add-ons. It works with FEBE – Another backup tool for Firefox. CLEO packages any number of extensions / themes into a single installable .xpi file – which contains all your add-ons. You can restore your add-ons later simply by installing the output XPI file.

Backup and restore your favorite Greasemonkey scripts on multiple computers easily.

I love MozBackup to backup and restore Firefox, but FavBackup can backup almost all major browsers.

Having multiple profiles in Firefox is really a nice idea. You can manage your life easily with this way. Also, if you share computer with others you must create separate profiles.

MozBackup is cool tool to backup almost everything related to Firefox. You can take backup, carry it anywhere and can restore on other computers.