Extending Firefox

The extensions or add-ons available in Firefox, are amazing. They extend Firefox beyond it's design parameters, making it highly customizable, and allowing you to make it your own. The only problem is, every time I install Firefox, I forget the name of at least one of my extensions, so I thought I would write them all down here.
There is an extension called: FEBE (Firefox Environment Backup Extension), which allows you to backup all of your extensions, and settings, but I prefer to install them myself and do the backup by hand, that way I know exactly what I have and where I have it.

My Top 15

1. Adblock Plus : https://addons.mozilla.org/en-US/firefox/addon/1865
Adblock Plus blocks adds, and banners from downloading to your computer, saving you from, waiting for adds to load on each web page, and unnecessary downloads. I'm never going to buy anything advertised in this way, (In fact, if I see a product advertised I go out of my way to not purchase it). Therefore I prefer not to be spammed by advertisements while I'm surfing.
This extension can be used by right clicking on an add and blocking it. Or by selecting a filter subscription when Adblock Plus starts for the first time. A filter subscription will block most advertisements automatically.

2. Bookmark Duplicate Detector : https://addons.mozilla.org/en-US/firefox/addon/1553
The Bookmark Duplicate Detector will detect bookmarks duplicates (by URL), when trying to add a new bookmark, as well as finding duplicates in your existing bookmarks. I like this little extension, if you have a lot of bookmarks this is very helpful.

3. Context Search :
https://addons.mozilla.org/en-US/firefox/addon/240
Expands the context menu's 'Search for' item into a list of all your installed search engines, allowing you to choose a specific search engine every time. This is really handy, I use it everyday, I can search for any word, in any of my installed search engines: from Google and Wikipedia to the Free Dictionary.

4. Copy Plain Text :
https://addons.mozilla.org/en-US/firefox/addon/134
If you've ever needed to copy the text out of a webpage, without the formatting (font colour, links, text size, bold, italic etc.) Then this extension is for you. It adds an option to your context menu which allows you to copy the text on a page without formatting at all. It is so very handy, especially when copying text to blogs, or word processors.

5. Customize Google :
https://addons.mozilla.org/en-US/firefox/addon/743
Customize Google enhances Google's search results by adding extra information (like links to Yahoo, Ask.com, MSN etc) and removing unwanted information (like ads and spam). All features are optional and easily configured. You can watch a short introduction movie at:
http://www.customizegoogle.com, for more information.

6. Downloadhelper :
https://addons.mozilla.org/en-US/firefox/addon/3006
DownloadHelper is a tool for web content extraction, it can capture video and image files from many sites around the web. When DownloadHelper detects a downloadable file, the DownloadHelper icon becomes animated and a menu allows you to download files by simply selecting the item you would like.

7. Download Status Bar :
https://addons.mozilla.org/en-US/firefox/addon/26
I don't like the Download window in Firefox, Download Status Bar, removes the need to use the download window. This extension allows you to view and manage all of your downloads from the status bar, either as tiny progress bars, or in mini mode, where just the number of downloads occurring, and completed are shown, I love mini mode. This is an awesome extension that I wouldn't be without.

8. Dictionaries :
https://addons.mozilla.org/en-US/firefox/browse/type:3
By default Firefox checks spelling in US English, however there are a variety of other language dictionaries available here.

9. Fasterfox :
https://addons.mozilla.org/en-US/firefox/addon/1269
Fasterfox allows you to tweak many network and rendering settings such as simultaneous connections, pipelining, cache, DNS cache, and initial paint delay. This is a very powerful extension, and can make Firefox perform even faster.

10. Flag Fox :
https://addons.mozilla.org/en-US/firefox/addon/5791
Flagfox shows a little flag icon in the status bar indicating the current website's server location. Clicking on the icon brings up further information from Wikipedia or Geotool, about the location. This is a cool little extension, which I never thought I would use, however, it is very intriguing, and I use it much more often than I thought I would.

11. Flashblock :
https://addons.mozilla.org/en-US/firefox/addon/433
Flashblock blocks all Flash content from loading on web pages. It leaves a placeholder on the webpage that allow you to click to download and view the Flash content. I wouldn't use Flash if it wasn't for this add-on, I like being able to choose what I download and when.

12. Gmail Manager :
https://addons.mozilla.org/en-US/firefox/addon/1320
Gmail Manager allows you to manage multiple Gmail accounts and receive new mail notifications. Displays your account details including unread messages, saved drafts, spam messages, labels with new mail, space used, and new mail snippets. All from your status bar, or toolbar. If you have more than one Gmail account this is very handy, I love being able to check my mail just by opening Firefox.

13. Menu Editor :
https://addons.mozilla.org/en-US/firefox/addon/710
Menu Editor allows you to rearrange or remove menu items from the context menu (right-click menu) and main menubar (File Edit View etc.) This is really handy if you have menu items that either you don't use or which are in bad places. I used it to remove the "Switch Page Direction" context menu, which I found particularly annoying.

14. Save as image :
https://addons.mozilla.org/en-US/firefox/addon/3408
This extension allows you to save a web page, or a frame, as an image. This can be really handy for showing people web sites, for debugging, or demonstration purposes.

15. Tabs open relative :
https://addons.mozilla.org/en-US/firefox/addon/1956
I love this extension, Tabs Open Relative makes all new tabs open to the right of the current tab, rather than at the far right of the tab bar. This way you can keep your work all in one place, and keep research in a relevant order.