Addons I find the most useful for my time browsing using my notebook.
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).
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!
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.
Make your bookmarks bar better. Roomy Bookmarks Toolbar can: hide bookmarks/folders name(dock like), multirow, autohide and many another features(more than 20).
Customize your bookmarks bar using one add-on.
Adds toolbar buttons to the customize toolbar window in several programs including Firefox, Thunderbird and SeaMonkey. Some of the buttons make commonly preformed actions quicker, others add new functionality.
StumbleUpon is the easiest way to discover new and interesting photos, videos, web pages and more, recommended by a community of experts. Tell us what you are interested in and we recommend page after page of amazing stuff you’d never expect to see.
Quickly test out your web pages in Internet Explorer, Chrome, Safari, or Opera. Open With opens the current page in your other browsers with just one click. Add Open With to your menus, toolbars and developer toolbox today!
Get international weather forecasts from AccuWeather.com and display them in any toolbar or statusbar with this highly customizable and unobtrusive extension.
CLEO (Compact Library Extension Organizer) is a Firefox extension that works with FEBE* to package any number of extensions/themes into a single, installable .xpi file.
Add a compact menu button to the navigation toolbar, and hide the menu bar.
Import/Export your Firefox extension preferences