Firefox Toolbar - adds Facebook search and activity notifications to Firefox. Also view friends and share content without visiting Facebook itself.

Facebook HugBack - makes all our pokes display as “hugs” - only visible to you, not your friends.

Notre Dame Facebook Style - a custom “University of Notre Dame” style that adds a custom header and theme to all Facebook pages.

Facebook Photo Album Downloader - download entire albums from Facebook with a click.
Boost for Facebook - adds all kinds of Facebook-specific features to your browser, including skins, notifications, auto-poke, auto-login, friends in your sidebar and more.

Facebar - another Facebook toolbar with automatic login, search and quick links.

Firefox Universal Uploader - a tool to upload and download images to many online services, include Facebook.

Autoslideshow - grabs all the images from the current page and displays a slideshow of them within Firefox. Works with Facebook and lots of other photo sites.