Also recommended earlier, Download Statusbar: https://addons.mozilla.org/firefox/26

Finally, Cooliris for previewing images https://addons.mozilla.org/firefox/2207

click the little green check mark in the bottom right of your browser window for a little surprise ;)

Firebug — of course

Web Developer Toolbar — don’t use it as much as I used to before Firebug came along

ColorZilla — use all the time, that or xScope for OSX

Google Sync/Foxmarks — I was using just Foxmarks but switched to Google’s offering for the password/bookmarks syncing

Greasemonkey/Stylish — cuz its awesome being able to mod other people’s sites to your will.

Adblock — nuff said

Download Sort — Auto sort files that I download (much like Hazel for OSX, but specifically for Firefox, plus I had problems with Hazel sorting faster than Firefox could download and it causes corrupted files)

Download Statusbar — keep up with your current download status

Fasterfox — though i haven’t noticed huge speed increases, but it does give me a handy dandy load counter

Forecastfox — though it’s currently disabled due to its long extension load times (i need a good low cpu/low ram alternative, thinking GeekTool for OSX)

Flashblock — like Adblock but for flash

OpenBook — Bookmark dialog window modifcations, lets me bookmark pages into my bookmark folders without the need of the mouse (what can i say, i’m going for that no mouse, all keyboard navigation technique)

PDF Download — though not necessary for OSX anymore, I use it on my work laptop (Windows).

IETab — a must for windows users for IE in a Firefox tab

User Agent Switcher — more development related tools

View Source Chart — one more development related tool

Tab Mix Plus – lots of extra tab options, though not as necessary since Firefox 2.0 introduced many of the options that Tab Mix Plus provides.

I need to cut all of these extensions down even more, probably cut out a lot of the ones I rarely use, like User Agent Switcher or View Source Chart or Fasterfox (the speed increase is not even noticable for me)

Also Firebug it’s incredible, I’ve seen a lot of positive reviews, but I just can’t install it on my mac, the extension does install but I can’t run it, or maybe I don’t know how to use it, I go to the Tools menu > Firebug > Open Firebug, but nothing happens! Aaargh!

Download Embedded – https://addons.mozilla.org/firefox/1993/
DownThemAll – http://www.downthemall.net/
Web Developer – https://addons.mozilla.org/firefox/60/
Firebug – http://www.getfirebug.com/
Google Browser Sync – http://www.google.com/tools/firefox/index.html (helps with multiple computers)
Add N Edit Cookies – https://addons.mozilla.org/firefox/573/

I used to be a really big All in one Sidebar fan, but not really anymore. No real use anymore for it.

Yea, i’m a Google whore, i used to have the Google web accelerator installed, but that regurally took over my computer’s memory, and i never really noticed the “faster loadings” of pages, i just like the “You’ve saved 3.2 days” line at the top of Firefox.
I also have Google Browser Sync on my other computer, it’s saved me a few times when i reformated because now i dont need to backup my bookmarks/passwords, but i haven’t installed it yet on my main computer.

Stumbleupon is by far, my favorite, and i use that on a daily basis, i have found thousands of new and interesting sites through it.

I used to use Web comments to see if anyone was linking to my site: http://steve.dedlycomputer.com/microwave but really, i don’t know why i have it anymore.

Notebook comes in handy for when im too lazy to save the info to a text file on my desktop.