Ad-ons I'd recommend: Ad Block Plus - never worry about seeing advertisements on websites again. Coral IE Tab - for those sites that just don't work in Firefox (there's just too many sites designed specifically for IE that this one is essential). CoolIris is beautiful eye-candy. After that, it depends on how clever you want to get. If you're working between multiple computers, Weave is a good way to keep everything synchronised. Developers should have the Web Developer Toolbar and a few others. JSView is a good developer tool as well (though it claims not to work with the new Firefox, I've had no problems). Firebug as well... As a site designer I use Firefox to make sure everything works, IE when I'm forced on to Windows (I'm normally a Linux user) and Chrome and Opera for testing purposes.