Blocks annoying video ads on YouTube, Facebook ads, banners and much more.
Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).
LastPass, an award-winning password manager, saves your passwords and gives you secure access from every computer and mobile device.
Tab Mix Plus enhances Firefox's tab browsing capabilities. It includes such features as duplicating tabs, controlling tab focus, tab clicking options, undo closed tabs and windows, plus much more. It also includes a full-featured session manager.
Xmarks is the #1 bookmarking and open tab add-on. Keep your bookmarks, and open tabs backed up and synchronized across computers and browsers. Mobile phones with Premium access. Utilize LastPass to sync passwords!
A light-weight Google search toolbar for Firefox. Offers 14 search types, Google search suggestions (in 5.0+), search history auto-completion, a customizable toolbar, search word highlighting, and more.