Addons, An addon is a piece of coding that adds customized features or increases features in Firefox, these are my recommendations and most of them improve or customize firefox for the better.

Adblock Plus
Ever been annoyed by all those ads and banners on the internet that often take longer to download than everything else on the page? Install Adblock Plus now and get rid of them. Right-click on a banner and choose "Adblock" from the context menu - the banner won't be downloaded again. Maybe even replace parts of the banner address with star symbols to block similar banners as well. Or you select a filter subscription when Adblock Plus starts up the first time, then even this simple task will usually be unnecessary: the filter subscription will block most advertisements fully automatically.
Download URL: https://addons.mozilla.org/en-US/firefox/addon/1865



Download Status Bar
View and manage downloads from a tidy statusbar - without the download window getting in the way of your web browsing. Despite its compact size, Download Statusbar packs in more useful features than the standard download window. The fully customizable interface auto-hides when not in use, allowing full control without interruption.
Download URL: https://addons.mozilla.org/en-US/firefox/addon/26



IE Tab (Add's the ability to view "Internet Explorer" only pages in Mozilla Firefox)
IE Tab - an extension from Taiwan, features: Embedding Internet Explorer in tabs of Mozilla/Firefox... This is a great tool for web developers, since you can easily see how your web page displayed in IE with just one click and then switch back to Firefox.
Download URL: https://addons.mozilla.org/en-US/firefox/addon/1419



DownThemAll!
The first and only download manager/accelerator built inside Firefox! DownThemAll is all you can desire from a download manager: it features an advanced accelerator that increases speed up to 400% and it allows you to pause and resume downloads at any time!

DownThemAll is fast, reliable and easy-to-use! It lets you download all the links or images contained in a webpage and much more: you can refine your downloads by fully customizable criteria to get only what you really want!

DownThemAll is absolutely freeware and open-source. No Adware, no Spyware.
Download URL: https://addons.mozilla.org/en-US/firefox/addon/201



FasterFox (This is the single Addon that makes Firefox twice as fast.)
Performance and network tweaks for Firefox.
Fasterfox allows you to tweak many network and rendering settings such as simultaneous connections, pipelining, cache, DNS cache, and initial paint delay.

Dynamic speed increases can be obtained with the unique prefetching mechanism, which recycles idle bandwidth by silently loading and caching all of the links on the page you are browsing.

Download URL: https://addons.mozilla.org/en-US/firefox/addon/1269
Note: It will auto configure Firefox to the maximum speed for "Your" specific connection upon completing the installation.


Tab Scope
Shows a popup on tabs and enables you to preview and navigate tab contents through popup. Major features are:

* Real-time preview of tab contents
* Navigate (Back/Forward/Reload/Stop) through popup
* Scroll pages or frames in preview with mouse wheel
* Click links or buttons directly in preview

For more info, please see http://www.xuldev.org/tabscope/ Download URL: https://addons.mozilla.org/en-US/firefox/addon/4882


Translator (Translates any Language into English)
Translator is web translation extension that allows you to translate any web page into nearly any language at the click of a button.

Currently supports the following online translation services:
* Google Translation
* Yahoo! Babelfish
* PROMT
* freetranslation.com
* Altavista
* Im translator

Supports the following locales:
en-US, fr-FR, de-DE, it-IT, nl-NL, pt-BR, hr-HR, zh-TW, zh-CN, ru-RU, es-CL, es-ES, es-AR, tr-TR, uk-UA
Download URL: https://addons.mozilla.org/en-US/firefox/addon/3361


FoxTorrent (Great for Pirates unless they use a stand alone client program other then BitTorrent, uTorrent, Azerus, BitComet, etc)
Download torrents right in Firefox! A full featured BitTorrent client integrated into Firefox. Allows you to stream videos in torrents!
Supports Windows, Mac, and Linux.
Download URL: https://addons.mozilla.org/en-US/firefox/addon/4844



Extended Statusbar
A Statusbar with Speed, Percentage, Time and loaded size (like in Opera) Adds an Opera-like statusbar to Firefox that shows:
*number of loaded images
*bytes downloaded
*average download speed
*Load time
*percentage of the page loaded
Download URL: https://addons.mozilla.org/en-US/firefox/addon/1433