It's the Web Developer Toolbar. I just recently wrote a post about it. Here is a link to their site: Web Developer Toolbar
I like the VOICE recognition add-on which brings the google results as soon as it hears our search term. Easy to use! Also it automatically saves the result URLs and their meta tags, page rank information, whois information of that website, contact email address, full postal address in excel / csv / access format. Everything done automatically. No need to type anything. Once installed this add-on, even if you shut down the system, as soon as it hears switch-on, it automatically reboot our system and opens the firefox. So everything runs according to our voice. Nice one. I like it very much. Itz completely FREE. If we go for the paid version, it automatically search the outsource freelancers and get whatever we want services like SEO, web design, data entry, etc., and contact them on behalf of us. If we store our paypal user name and password in it, eve it automatically send the payment to those whom we want to send payment by automatically logging in to our account and send from there easily and quickly. (supports mass payment too!) Everything using single key word(s). I heard that if we go for VIP premium service, it even come and feed us food & milk everytime.
This is a good point when installing these add-ons. be sure to remove ones you don't like or don't use much. Every time you start up FF it checks to see if there are any updates on every add-on you install. The more updates you have the longer it takes, especially if you have some that get updated frequently. While this is actually a good feature of FF, it is also a pain in the but when you have to frequently wait for updates. FF is also a bit of a memory hog, Each add-on takes more memory. If you use multiple windows each window increases the memory taken by the full amount. Tabs don't take as much but still greatly increases the memory. Bottom line. Only keep the add-ons you actually use.
youre right mate...thats why im only load some add-ons depend on what im currently doing...ex: when im doing some web development/design im using firebug and web developer add-on,when im work on my SEo campaign im using seoquake add-on,but when im just browse and surf im unloaded all of my add-ons..
LinkChecker is checking all links on a Website and you can make exclusions (logout, etc.) https://addons.mozilla.org/de/firefox/addon/532
See Top 22 Firefox Add-ons for Web Designers & Developers. In this you will get my favorites addons I use.