One of my favorite Firefox features is the ability to add browser extensions to it.
Firefox extensions are basically free extensions that you can add to your browser that add additionally functionality (usually extended functionality that doesn't exist in any other browser).
Here's my list of favorite Firefox extensions (this list will probably grow):
- All-in-One Gestures - lets you control your browser by using mouse gestures
- BugmeNot - seamless integration of BugmeNot.com into forms that require registration to access
- IE View - open the current page in Internet Explorer
- Firefox View - add a context menu item to IE that lets you view the current page in Firefox
- LinkPreview - shows thumbnails of link targets
- Web Developer - tons of web developer tools (editing CSS, disable forms...)
- Down Them All - download all links in a page
- TargetAlert - shows a visual indication of a link target (whether it is a link to a pdf file, RSS file...)
- TabBrowser Preferences - add additional control to Firefox tabs (like the default page to load in a new tab...)
- LiveHTTPHeaders - another web developer extension. Lets you view and edit the http headers that the browser sends
- Session Saver - saves all the open tabs when the browser closes so that the next time you open the browser all the sites you were surfing will reopen
- Aardvark - lets web developers easily view information about elements in the page
