Reese

I'm only using 2 addons atm.

The first one is called Flashblock. Basically, It stops flash files from automatically starting. It gets rid of all those punch the monkey ads and other annoying things. It adds a placeholder in place of the flash file so you can load the flash movies/games you actually want to watch. You can also set a list of websites it'll automatically allow. Very handy.

The second is called Splash! When you open Firefox it pops up a little firefox logo and a loading bar. Before getting this addon, I don't know how many time I set and wondered if I actually double clicked the firefox shortcut.. Now I know every time

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“It is better to be rich and healthy than poor and sick” - Dave Barry

Vigilante

I use:
Colorzilla for hex color values
Web developer
Adblock plus
CS lite for cookie permissions
FireFTP for website and gameserver uploads
Flagfox to see what country the site I am visiting is in
Forecastbar enhanced for weather
Oldbar to fix the annoying FF3 address bar look
Password exporter to import/export passwords when I format
and
PicLens for looking at google images as a massive moving screen of whatever the hell I want. Think "boobies", and make it a huge black scrolling screen of boobs. Best. Addon. Ever.

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We contend that for a nation to try to tax itself into prosperity is like a man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill

Jetée

Very helpful. I am not too sure why there isn't a thread about this already, but I'll contribute here until proven otherwise.

Admittely, I mainly use Opera for the bulk of my surfing, but I am trying to learn the intracies of all the appropriate addons that will aid me in loving Firefox (Opera truly spoils me because it is fully-functional with many features that addons for Firefox are actively trying to copy so as to mimic all the features Opera already has integrated).
But, I am sure there are some very innovative programs that will push me to becoming a dual-browser.


I don't use very many addons either. This is one that seems very appealing to me, since it perhaps was created in tandem with AdBlock Plus, which I use along with a list provided, to rid most of the above-ground net of pesky ads.



I also have an addon very similiar to this, though I have used it before(supposedly you use it visit a missing site, which may have been archived by the wayback machine).


Add to Search Bar - use a search engine so often it hurts to type it in address bar; make it simplified by not wasting a bookmark, but by incorporating it directly to the default search bar.

Answers.com add-on - for the archaeologist/absorber of antiquities within me

Cooliris Previews - I don't use this at all either, but when I eventually need to... [preview a link's contents by hovering over it, but without clicking it]

del.icio.us Bookmarks - Access your bookmarks wherever you go and keep them organized no matter how many you have

StumbleUpon Toolbar - just happened to find something interesting; share it.

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As human beings, our greatness lies not so much in being able to remake the world (that is the myth of the Atomic Age) as in being able to remake ourselves.

—Mohandas K. Gandhi

ratbastid

Most of my web development work would be a thousand times harder without the Firebug plugin. You can watch the HTTP transaction happen in realtime, including inline "AJAX" actions. You can walk the document's DOM, alter javascript on the fly.... Beautiful thing.

Redlemon

BugMeNot: I haven't used this much recently, but if you want to enter a password-requiring news website, this can allow you to skip the login. You know you were just going to lie about the demographics anyway.

Download Statusbar: It puts an item in the statusbar for each item you download, with a progressbar and a new color when it finishes downloading. I find it far more convenient than even the Ffx 3.0 built-in notifier.

Linky: Open all image links in individual tabs. Best way to surf TGP porn sites. Also good for selecting a range of links and opening them simultaneously.

Make Link: Right-click access to perfectly-formatted [ url ] links for posting in forums like this; critical for an obsessive librarian like me.

Nightly Tester Tools: I'm not testing Firefox 3.1 yet, but this is handy for that.

Picnik: Right click an image, upload it to an online editor, post it for inclusion in a forum.

Prism: Prism? What the heck is this doing here? I'll go ahead and uninstall that.

Resizeable Textarea: Although it doesn't work on this site, on most sites, you can change the size of a textarea box to make it easier to see everything you typed. Here, you can just use the doublearrow buttons instead.

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I can't read your signature. Sorry.

Cynthetiq

I don't use FF very often, but what I do use it for is huge as I can't find anything IE that does this.

Firebug: helps me understand CSS and HTML layouts in forums.

__________________
I don't care if you are black, white, purple, green, Chinese, Japanese, Korean, hippie, cop, bum, admin, user, English, Irish, French, Catholic, Protestant, Jewish, Buddhist, Muslim, indian, cowboy, tall, short, fat, skinny, emo, punk, mod, rocker, straight, gay, lesbian, jock, nerd, geek, Democrat, Republican, Libertarian, Independent, driver, pedestrian, or bicyclist, either you're an asshole or you're not.

Speed_Gibson

Two of my favourites are Noscript and Firebug, those are the main ones that I miss in Opera which I typically use.
edit: just noticed that the new Opera feature (as of 9.5) called dragonfly is similar in functionality to Firebug; not sure if you can edit settings and see the changes on the fly though.

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Started talking to yourself I see.
Yes, it's the only way I can be certain of an intelligent conversation.

Black Adder

PlanG

Noscript
Adblock

Greasemonkey + various scripts (from userscripts) which destroy facebook annoyances such as ads, "people you may know" and fixes the top bar so it moves with the screen
Quickdrag - select text and drag it, this opens a tab with a google search of the text.
Better GMail adds useful things, and removes crap
Better Youtube same as above - also adds "download as MP4" link, straight from youtube iirc (or it may be a greasemonkey script)
British English Dictionary - spell checker for forms etc
stylish - apply your own styles to websites (or other people's from userstyles)
customise google - gets rid of adds and other annoyances. Makes google image thumbnails link directly to the image.

LoganSnake

Only AdBlock Plus and Download Statusbar.

I will definitely install PicLens when I get home. Looks awesome. My work computer crashes FireFox when I try to run it here.

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Maturity is knowing you were an idiot in the past. Wisdom is knowing that you'll be an idiot in the future. Common sense is knowing that you should try not to be an idiot now. - J. Jacques

dirtyrascal7

Besides what is listed above, I use an Add-On called "Image Zoom" which allows you to shrink or enlarge images within a webpage with a simple right-click.

__________________
"Tie yourself to your limitless potential, rather than your limiting past."

"Every man I meet is my superior in some way. In that, I learn of him."

heyal256

I'll mention these since they haven't been mentioned above

DownloadHelper 3.2
Firesomething 1.8.0
FlashGot 1.0.4.5
Forecastfox 0.9.7.7
IE View 1.3.7
InfoLister 0.10
Popup ALT Attribute 1.3.2008052801

Bear Cub

Fasterfox, Tabbrowser Preferences, and gmail notifier. The tab preferences are my favorite, as I hated opening a new tab and not having it load Google by default.

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Living in the United Socialist States of America.

Vigilante

Yeah I forgot to mention gmail notifier. I use that one too.

__________________
We contend that for a nation to try to tax itself into prosperity is like a man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill

MiSo

i love mouse gestures.

i mainly use it to close tabs quickly.
it lets you input a mouse command to perform certain fuctions while broswing.

example: i set the add on to close a tab when i hold down right click and scoll down + release right click.

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- this space for rent -

snowy

Forecastfox is about it for me but I'll be checking out some of these other ones, I'm sure.

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If I am not better, at least I am different. --Jean-Jacques Rousseau

MikeSty

I used to load up with extensions, and I had a lot of stupid ones, but now I prefer streamlined. I use the MostlyCrystal theme and have given myself some more viewing space by switching to the top-right Googlebar as opposed to the one that had it's own bar below Favorites. I run FireFox 2 (FF3 was fail)

Here's the short list of extensions:
IE Tab (I don't use it very often, but it comes in handy. Embedded IE tabs are nice)
Google Notebook (I've abandoned my old "favorites" with the exception of the bookmarks toolbar, and use this to save important things. I make a habit of deleting old entries.)
DownThemAll
Adblock Plus

spindles

Agreed - my dev life would be a lot worse without firebug.

I also have a plugin called NetUsage. It keeps track of how much I've downloaded each month (Net Usage Item - Firefox Internet Usage Extension). Only useful for Aussie ISPs I think, so probably mostly useless for just about everyone here.

Plus I've got the Aussie English dictionary plugin - because Americans are useless spellers

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who hid my keyboard's PANIC button?

MacGyver

Flash and Video Download - Download youtube videos and more

ImageHost Grabber - downloads all the images on a page of thumbnails that reference an image host sites like photo bucket

Save Images - if you have a thread where someone posted a bunch of pictures you like, you can save all the pictures on that page in one step. it does more, but that's what I mainly use it for.

__________________
More is more and less is less,
More is better and twice as much is good too.
Not enough is bad,
And too much is never enough unless it's just about right.

Cynthetiq

saved me mucho dinero!

__________________
I don't care if you are black, white, purple, green, Chinese, Japanese, Korean, hippie, cop, bum, admin, user, English, Irish, French, Catholic, Protestant, Jewish, Buddhist, Muslim, indian, cowboy, tall, short, fat, skinny, emo, punk, mod, rocker, straight, gay, lesbian, jock, nerd, geek, Democrat, Republican, Libertarian, Independent, driver, pedestrian, or bicyclist, either you're an asshole or you're not.

Xerxys

flat5

Hello Xerxys,

How is this better than Ad Block+

Xerxys

^^Wazzup!

SimpleBlock prevents URL's from loading. I used AdBlock+ for a short while and my experience wasn't satisfactory.

AdBlock+ didn't work for me. Especially when I am searching for something especially obscure on the net or visiting my beloved porn hub, it does not block the pop ups or possible pornadoes (if your still on WinXP). Now that I am on windows seven, I use Chrome as a browser and that serves it's purpose well but I TFP and watch TV on firefox so any popup's that err ... pop-up are blank and do not draw any data from their intended sources.

flat5

I use xp & firefox.
Ad Block works for me unless the page or file name changes on each load.
Regular expressions might help in that case but I don't think so.