Do you connect to various internet connections that require different proxy settings? Are you fed up of having to manually change these proxies all the time? The Switch Proxy Tool, for Firefox is the answer. It allows you to create profiles for each proxy and quickly and easily change between them. This is a must if you are switching between a Uni and Home connection (TIC!!). Hope this helps you Link 

Do you use FireFox on more than one machine? If like me you do then this app is great. Its a little add-on that syncs your bookmarks on each instance of FireFox you have installed, whether that be Windows, Mac or whatever!! This should definatly be included as standard for future releases. Keep watching for more of the best FireFox add-ons.