These are just a list of Mozilla Firefox extensions I use on my box
1) Abduction: Right click on any webpage and "save page as" an image, a complete / part of a webpage.
2) Downloadhelper: Downloadhelper can capture images and files from soooo sooooo many sites.
3) ABP: AdBlockPlus - ban/block those anonying adverts into oblivion.
4) AnonymoX: if sometimes you might want to relish in "invisibility", this is just right for you
5) FoxClocks: provides a neat clock display just below your browser
homepage: http://foxclocks.org/ ex: below
6) Wappalyzer: if you are always as curious as I am when I arrive at a webpage and wonder: "how did they do that?", wappalyzer provides details of what web-technologies are used.
7) Web Developer: speaks for itself. Its a tool every web developer must have.
8) Torrent Finder Toolbar: provides a nice way to search for torrents from your browser
9) IP address and Domain Information: just in case you like sniffing around, this tool provides the geolocation, DNS, whois details, routing, hosting, domain neighbors, etc., as well as your own public(LIVE) IP address.
10) Download Youtube Videos as MP4: does this need any further explanation?