I was switching between computers last days, also reinstalling OSes few times and I needed to get rid of bad feeling when I need to set up Firefox and all its extensions and bookmarks again and again. Hopefully FEBE add-on helped very much. With FEBE you can easily backup and restore all of Firefox settings, data, extensions, themes, in one word completly backup and restore whole Firefox.
“FEBE (Firefox Environment Backup Extension) allows you to quickly and easily backup your Firefox extensions. In fact, it goes beyond just backing up — It will actually rebuild your extensions individually into installable .xpi files. Now you can easily synchronize your office and home browsers.”