Post them!

Mine are:

ADBLOCK
Paste and Go
Download Manager Tweak
Enhanced History Manager

I feel all of the above are NECESSARY as a FF user

These are just really useful especially to me:

Statusbar Clock
Webdeveloper Toolbar
ForecastFox

Adblock is the coolest extension ever. For instance, you can use it on a certain, shall we say "Stealth Videogame Player" company's ads making the massassi forum much prettier and less slow in the case of the occasional flash. This works on so many sites and just makes it as if the ads never existed. FINALLY a decent tool to clean up the internet. No popups by default in firefox, and adblock really cleans up everything like never before.

I'm running a bunch of different versions, so my extensions are all mixed up. I guess I'll make everything up to date when I get back to school and broadband.

My favorites 0.8-1.0:

Launchy
Tabbrowser Extenstions
Things They Left Out
WeatherFox
Mouse Gestures
Toolbar Enhancements

I don't really use any extensions. i've trained myself over the years to ignore the ads, so its not something i really think about. Firefox kills popups by default, too, so I've been popup free for over a year.

try adblock, its so cool. all you have to do is right click, add some *'s for wildcards, and the banner disappears! forever!

ScrapBook - <3
FoxyTunes
ChatZilla

*runs off in search of AdBlock*

[Edit - I found it. Wow. My life is complete]

Tabbrowser Extensions.

Mandatory:
Radial Context Menus
UndoCloseTab
MiniT (for drag+droppable tabs)

Others:
Adblock
Compact Menu (to get it to look like this)
Nuke Anything (for cutting non-blockable ads from the middle of pages, etc)
Image zoom

close tab on double click

Best. Extension. EVAR.

Others:
Adblock
Nuke Anything
Download Statusbar
Statusbar Clock (a clock for each monitor, comes in handy, since I always leave firefox open, and I can see the time on my second monitor via Firefox while playing a game on my primary monitor.)
IE View
Popup ALT Attribute
Diggler

Adblock is awesome. There's a premade set of compact filters here, updated constantly. Also, BugMeNot. Bypasses annoying free registrations.

I still have an old version of Firefox, if I upgraded to a newer version would all of my extensions carry over?

The extensions I regularly use are:
FoxyTunes
ScrapBook
fireFTP
ChatZilla
WeatherFox
Linkification (makes all text starting with [url]http://[/url] into links)
Download Sort
Tabbrowser Preferences

i kinda assumed tabbed browser prefrences was just assumed. heh...

i have sage rss reader too. awesome.

I vote this thread gets put with the useful programs thread and kept for prosterity. For it is helpful and good.

I'll have to look into some of these mentioned.

I used to have a lot more, but I just got a new computer and didn't bother finding all of them again.

er forgot the thing

some not all

Well I know I'm a little late to post (always being mindful of the hovering thread-necromancy angels ;)) but the only extensions I use (at present, although I'll certainly have a look over the others :)) are "DOM Inspector 1.0" and "Sage 1.3". I can't state enough how much I love Sage for its RSS feed management - it's fantastic for testing my own RSS feeds out on and when I next have some free time, I intend to write a program that will combine blogging power with RSS (certainly not for a while yet though - way too busy with scary "Real Life" TM work at the mo :rolleyes:... )

That and Sage helps me keep track of MegaTokyo updates :D. Seriously though, I think RSS is something that we're going to see hugely increase, certainly from a website design/development p-o-v

Just my tuppence worth for the day

-Jackpot

i've got the sage. it's really really handy.
i've got cbc, wired, sitepoint and a couple of others on there.

Someone needs to make something to...convert flash into text.

Computer game developer websites are especially awful, being totally flash-driven. Some don't even have any non-flash alternative. These sites make me weep, as usually I'm just looking for a link to a patch or something. I desperately want something to parse through the flash crap and output only the text with appropriate links, lynx-style.

Flash navigation should be illegal.

Adblock
Thumbs
miniT
Nuke Anything

Another vote for ScrapBook. Using it this very moment.