This is just a quick, minimal list of what firefox extensions I install for use in my day to day Web Development work. While some of the extensions may not be related to Web Development, they could be seen as essential convenience extensions.

Here’s the top ten in the order of how I install them (I’m not going to do a countdown as it’s so very “the late show with David Letterman”) on a brand new installation of Firefox on Ubuntu, Windows, Fedora or any other operating System that supports Firefox.

1. Restart Firefox: https://addons.mozilla.org/en-US/firefox/addon/1249
   Every time I install a new extension, I know that I will have to restart firefox and that sometimes the “restart firefox” button that comes with the firefox add-on manager is temperemental and does not work, this extension does the trick – all I need to do is go to file then click on restart firefox and I’m there.
   
2. New Tab Homepage: https://addons.mozilla.org/en-US/firefox/addon/777
   Nothing more annoying than opening a new tab and getting a blank white window instead when you’re used to opening a new tab and seeing your home page (I have mine set to google). This extension gives me a fix. I know that there’s a google field next to the address bar, but I like to do the old CTRL + T and start searching (google has directed focus onto the search field when you navigate onto their site) .
3. Download Statusbar: https://addons.mozilla.org/en-US/firefox/addon/26
   Like the first two extensions, this is a convenience feature. It neatly displays your downloads just above your status bar. Something which I prefer personally over the popup download window.
   
4. Fasterfox: https://addons.mozilla.org/en-US/firefox/addon/1269
   Fasterfox has been heralded to handle performance and network tweaks for the firefox web browser. I just install this out of habit.
   
5. Live http headers: https://addons.mozilla.org/en-US/firefox/addon/3829
   I didn’t think much of it when I first installed it, but the more my development started leaning toward header manipulation, the more I found it useful to just open that up and watch the information scroll through when I have capture enabled for later analysis.
   
6. Web Developer: https://addons.mozilla.org/en-US/firefox/addon/60
   ’nuff said. If you are a web developer, then you will find lots of useful tools in this extension, such as window resizing, form analysis, validation tools, css and javascript information and manipulation – I could go on, but I’m not going to – check it out now to see for yourself.
   
7. Firebug: https://addons.mozilla.org/en-US/firefox/addon/1843
   Firebug was brought to my attention by Ben Rowe in late 2005 – early 2006 and it has stayed in my collection since! A very nice little tool for debugging and just getting general information about open web pages in your browser. Just like the Web Developer Toolbar extension, it’s a must have. Good for javascript debugging, on-the-fly editing and viewing for css and html. To top it off it is a very mature JavaScript debugging tool (well as mature as extensions come anyway).
   
8. HTML Validator: windows: https://addons.mozilla.org/en-US/firefox/addon/249
   linux: http://users.skynet.be/mgueury/mozilla/download.html (yes, it’s available for linux!)
   I was over the moon when I found out that they finally sorted things out with the linux version. This HTML Validator extensions now comes in both Windows and Linux flavours – it does what it says it does and “validates HTML” What I like about this is it’s supports validation for using either SGML or tidy Validation rules or “Serial” which means both! It validates using Tidy validation rules, then once that’s all satisfied, it validates your page against SGML.
9. Measureit: https://addons.mozilla.org/en-US/firefox/addon/539
   MeasureIt is a good plugin. For example, when I’m looking at a graphic and want to get some quick dimensions, I can just click on the MeasureIt icon on the bottom left of my browser and launch into measure mode which gives me a draggable rectangle box and its dimensions. Very handy when you’re doing Web Production work.
   
10. Dummy Lipsum: https://addons.mozilla.org/en-US/firefox/addon/2064
    Ever mashed up your keyboard frantically for a few seconds to provide some copy or type up fake messages to copy and paste over and over? This extension puts an end to all that by providing you with latin text to represent actual copy on your web page. Easily accessible from Tools >> Dummy Lipsum. A very nice convenient feature.

To conclude, most of the extensions seem to be pretty obvious choices – I mean, as a Web Developer, it’s a no brainer that Web Developer firefox extension is added. What I found surprisingly useful however, is the Live HTTP headers firefox extension. After I got used to it and actually appreciating the data it’s giving me, I found it to be quite valuable.

This is just a short list – I plan to do some highlights on a couple more as I come across them, stay tuned for more to come.