My favorite Firefox extensions

Here are my Firefox extensions:

Download status bar
Display download details in the status bar. You can indicate with colors what the status is of a download (e.g. in progress, completed, interrupted).
IE tab
Switch the current tab between Firefox or Internet Explorer (which actually loads IE). You can set predefined URLs (such as Windows Update, etc).
Firebug
I can't see myself without it; when I use IE, I miss it. This handy tool lets you view and (temporarily) modify CSS and markup to view the results. But it is much more than that.
Web developer
Handy tools for web site development.
Delicious bookmarks
Speaks for itself. A must-have if you're a Delicious user.
Customize Google
Allows some customized settings for Google sites.
CS lite (Cookie Safe light)
Handy cookie control. At some point the regular version was not available (yet) for the Firefox version I was using at that time so I downloaded the light version instead and stuck with it.
Tab mix plus
Highly configurable tabs.
Redirect Remover
Cleans up links with redirects. Easy to override for single links.