My favourite and essential FireFox Extensions listed in no particular order.
Combines a swag of tweaks to Google Gmail in one FireFox extension. Just provides some nice tweaks to Gmail that makes it a little easier to use.
English (Australian) Dictionary
So FireFox know what the hell I’m on about mate!
Hate it when the posted URL or email is plain text and not clickable? This little baby will change that for you automagically!
Because some people just have to be stupid and make life hard by requiring IE. Haven’t they heard of standards?! This will save you the trouble of having to open IE for those one off websites, by loading IE into a tab. Can also set a list of sites to force load into an IE tab.
Without this I’d likely still be using Opera. Being able to open, close and reload with the click’n'flick of the mouse saves me a great deal of time everyday.
Restore Scroll Position
I was so glad when I finally found this extension. It was bugging me for ages that Firefox would not remember where I was on the page when I flicked back to it in the history. This solves that little annoying bug.
Download manager that also supports multi threaded downloads. Makes handling all the crazy downloading I do easier to manage and faster when multiple thread transfers are supported.