Best Firefox extensions?

[risingangel]

Some of my favorites are:
Grease monkey
https://addons.mozilla.org/en-US/firefox/addon/greasemonkey/

Foxytunes - for controlling external played and sites like Pandora and Youtube.
http://www.foxytunes.com/

Down Them All - mass downloading
http://www.downthemall.net/

Text-To-Image - Great for forums that don't allow for images.
https://addons.mozilla.org/en-US/firefox/addon/text-to-image/

[Q_Continuum]

As documented here: http://outspokengeek.net/?q=node/7

Firefox Sync - https://addons.mozilla.org/en-US/mobile/addon/firefox-sync/
BarTab - https://addons.mozilla.org/en-US/firefox/addon/bartab/
  On browser restart, only 'loads' page for active page, and leaves loaded by default.  (So the other 147 you had open don't waste time loading, just the tab entry; can hand-unload tabs, and can configure a unload timeout & whitelist for same to never unload - stupidly useful when having too many projects but not wanting to bookmark a set of tabs for a single use)
Tab Kit - https://addons.mozilla.org/en-US/firefox/addon/tab-kit/
  Vertical tabs, grouped based on where you clicked from.  Can collapse a group.  Waiting for this to get updated for 4.x...
HTTPS Everywhere - http://www.eff.org/https-everywhere
  Force HTTPS connections on a variety of sites.  Based on NoScript tech, intercepts links.
NoScript - https://addons.mozilla.org/en-US/firefox/addon/noscript/
  Stop the crap running, stop the infected ad banners running.
Greasemonkey - https://addons.mozilla.org/en-US/firefox/addon/greasemonkey/
  Mmmm.  Greasy monkeys...

[destined]

I too use bartab after someone else suggested it on one of the other extension threads. I love it! Now I do several different tab things that I am using with firefox, so I am working on figuring out which one or two I am going to keep since a lot of them do the same basic thing of helping you organize or group tabs. (and with bartab, they don't use excessive memory to load if you unload them before grouping them!)

I am currentling using tab king, tabgroups, tabkit, tab mix plus (disabled while I am using the others) multiple tab handler, tab colors. The tab colors are so nice when you have multiple windows open and different subjects going on. I can find colored tabs so fast!

And one last comment I just figured out (again) that ghostery & adblock plus both need to be weekly updated to keep up with the lastest bug, spam and ad definitions. So please do check up on that ocassionally.

[xenovalent]

I just opened up the "Add-ons" window in Firefox to check what I had.  Here's the list:

AdBlock Plus - removes most web ads, can disable on certain sites if you like
Beef TACO - Targeted Advertising Cookie Opt-out - sets opt-out cookies for major ad networks, restores them even if you clear cookies
Default Full Zoom Level - Changes the "default" zoom level from 100% to a selectable value (I use 120% because my eyes suck)
DownThemAll - as already mentioned, allows you to download many things at once
HTTPS-Everywhere (installed but disabled) - another one already mentioned, disabled because a lot of things weren't working right/I wasn't happy with the variation served on the "secure" websites in some cases
Long URL Please - turns "bit.ly/blAh1" type links into whatever it is that you're going to end up at
NoScript - JavaScript/Java/Flash/etc blocker, selectable control
Redirect Remover - similar to Long URL Please, but also turns links like "http://www.facebook.com/redirect?http%3A%2F%2Fwww.fark.com" into just "http://www.fark.com" so that places like Facebook can't track what links your clicking (again, can be selectively disabled, in case you want to allow a site to collect accurate statistics)
Tab Mix Plus - Many tab-customization options - in fact, I think that the functionality in this one should entirely be built into Firefox, and I don't understand why it isn't
User Agent Switcher - "This site requires IE8" - Not anymore, it doesn't!
Xmarks - Bookmarking synchronization services - it's possible to run your own server (and I really should) but I'm too lazy to bother - keeps all of my copies of Firefox (four different computers) using one set of bookmarks

BarTab looks like a good idea - I don't usually have more than about a dozen tabs open, but for the occasions when I do have large numbers of tabs, it could be very useful.  And last time I gave GreaseMonkey a try, it didn't ever seem to do anything...

[Anatomy]

Ant Video downloader for downloading any videos you want off the internet and straight into an encrypted folder. *Cough Cough*

http://www.ant.com/video-downloader/firefox

[CynEater]

The one plugin that should be installed is adblock plus as adds are created by evil arse holes that are almost as bad as Paleontologists 

Also the element inspector is good at blocking DIV and other bits on some pages

[HazmatChemist]

I have:
Adblock plus
BlackSheep
DownThemAll / DownThemAll Anticontainer
FoxyProxy
Greasemonkey
--AutoPagerize
--Rapidshare links checker
--Resizeable text fields
--Video embed
HTTPS Finder
HTTPS everywhere
NoRedirect
NoScript - can also use to force HTTPS on sites that HTTPS everywhere doesn't cover
ProxyTool
RefControl
TabMixPlus

[destined]

Anyone have any new Firefox extensions they want to note? I hope to update my list here soon because I have a bunch of new ones.

[Icehawk]

I think most of the ones I use have already been listed except for this:

BetterPirvacy - https://addons.mozilla.org/en-US/firefox/addon/betterprivacy/

Going back to an old NewsReal, Sean was talking about flash based cookies that you weren't able to clear like regular cookies and in some cases would check for and re-insert standard cookies of they were deleted.  This lets you pick through and delete any of those flash-based-fuckers you don't want and even has the option to dump them all when you close your browser.  If you hate having people track you on the net as much as I do, this one is almost a must-have.

[destined]

I have that installed but also have several other LSO and other flash cookies that i delete. I also want to add that I think a good SQL database cleaner is a good idea for firefox and other browsers. A number of cell phones and computers use SQL databases internally, so you can speed them up by clearing out useless data from them.

[Mindgrinder]

Tracking the trackers

http://www.networkworld.com/community/blog/track-trackers-collusion-interview-mozillas-ryan-merkley

[destined]

A show over at Galaxy15radio.com called Pure Decking was talking about this extension called Collusion a couple of months back. It is REALLY cool!