I do use firefox for browsing, but for making webpages i would suggest mozilla because it have a real javascript debugger, and a webpage editor wich isn t that great but allow to check the placement of tables and stuff.
But if you are on windows and are making webpages i would hightly suggest to install opera too , and regulary check compatibility with opera/mozilla/IE, if you can give a try to lynx, just to realize than things like forums are completely unbrowsables for some peoples ( lynx is a text only browser, so blind guys use it)