This is a list of the most useful FireFox extensions I have Found.
1.
Adblock Plus - So often now I go to a page I've found on someone else's computer to show them a cool site I've found; only to be hit with half a dozen banner ads that I didn't know existed. Adblock Plus is the best Plugin I've found. Hands down. It blocks everything you don't want to see (and, research has show you don't look at anyway).
2.
Bookmark Duplicate Detector - Warns you when you are about to bookmark a website you've already bookmarked.
3.
BugMeNot - Utilizes hundreds and thousands of user-submitted logins so you don't have to give your email address to every random blog you want to comment on. Or lets you comment without going through the lengthy signup process.
4.
CustomizeGoogle - Make Google (and its children) look how you want them to.
5.
DownloadHelper,
Video Download and
VideoDownloader - Various download services that simply fit into your right-click menu and let you download basically whatever you want. ie. Youtube videos.
6.
Draganddropupload - Instead of locating the file you want in some random folder somewhere on your computer, just drag it to the file name text box.
7.
Google Gears - Lets you download various Google eliminates. Such as your unread Google Reader posts.
8.
Greasemonkey - Don't like it? There's a script. Want it changed? There's a script. Wish it could do this or display that? There's a script. No Script? Write one. Greasemonkey scripts allow you to do and have just about any functionality you may want, for anything.
9.
Mr Uptime - I didn't think I would use this plugin at all. Boy was I wrong! Anytime I get to a site that can't be displayed, or is down for maintenance, or says to check back later. I use Mr Uptime. It checks the site for me until I can see it again and then it automatically opens the page for me. I use it all the time.
10.
StumbleUpon - The best time waster in existence (except maybe the Yo Yo); StumbleUpon allows you to discover new worlds you didn't know existed at the click of a button. Really!
You may never have a use for these, but it can't hurt to try. They work for me so they might work for you.
This is my answer to a comment I saw today, "I just want a browser that does everything out of the box."
I may or may not have mentioned PicLens before (I'm to 
FireFox three beta has been wonderful. But ever since beta release 5, it has been freezing all the time (two or three times a day). I wasn't having and problems, what happened?
GreaseMonkey is the greatest. I knew this back when I installed it the first time, but the more I use it (or don't use it [noticeably]) the more I love it. I recently installed the Google Big Brother script and get a kick out of it.
I upgraded to the newest version of Firefox 3 (beta version 3) and needless to say, I am impressed. The first Firefox 3 beta was impressive, it ran faster, cleaner, had better functionality, etc. But with this version comes an image change as well. Yes it is even faster, cleaner, etc. But this newest release makes it look new. It fits Leopard very well. It has a new sleek look, everything is smaller and more compact, and did I mention it's faster?
