Everyone has their own selections of Firefox extensions that makes their work-flow or surfing experience great. What I don't see a lot of is people posting the list that combined is their favorite or ideal web browsing tool.
I decided to put my list together, as we are "on the eve" of the release of a new version of Firefox, since in a few short months some of these may not work (until updated by the developers). This list is valid when using the Firefox 3.0.1 browser.
Here is my list:
Tabs Open Relative - this lets a "open in new tab" action produce a tab just right of it's parent instead of at the end of the lists of tabs. This is really helpful when doing google research and find multiple links you would like to follow from a single source page.
Snap Links Plus - This allows you to design a unique mouse selection/movement to draw a box around a list of links on a page. Upon selection, this extension opens the included hyperlinks in new tabs. In conjunction with the Tabs Open Relative extension, these just fold out just right of the active, or parent, tab.
Auto Clear Search Box - This extension automatically clears the searchbox in the navigation bar of the browser once used. I use this in a 3 step process. 1.) Use ctrl+k to activate the searchbox itself. 2.) Set "browser.search.openintab = true" in about:config, which opens a new tab independantly upon pressing enter from the searchbox. 3.) this extension then clears the seachbox and I am then able to repeat the process with minimum mouse/keystrokes.
***Note: you will have to register to install this one, no panic..it's free.
CustomizeGoogle - Well, this is for anyone who uses google's services. There are a great many customizations which can make that experience better and more secure.
Delicious Bookmarks - Well, online bookmarking is something you use or you don't. I do, to share links with others, remember research points or to collect information when troubleshooting an issue. This is a pretty good extension if you are signed up for the Delicious service.
Foxmarks Bookmarks Syncronizer - This is a smashing syncronizing tool. Makes all of your firefox installs on all your different computers. This tool syncronyses bookmarks and saved passwords. This is the tool that I moved to after google's Browser Sync was dropped from development. There is encryption for protection and there is need for an account from Foxmarks to let it work.
Gmail Notifier - does what it says, sits at the bottom of the browser offering a small unintrusive display of new messages. Supports multiple Gmail accounts and display prefernces.
ASNumber - Like it implies this tool displays the Autonomous System Number of the host where the website is. It also does a whois lookup to provide you with the information of the owner of the network where the website lives. Just remember that who owns the website and who owns the network may be different.
I find that this collection of extensions provide me with a great experience and enhances my surfing expererience. I hope this list might help someone put together thier favorite list of extensions too. Please add your favorite to the comments.