I mean really, the performance sucks! The Firebug add-on is a 600Kb+ download and it feels as if it really, really slows it down. I have for a while now switched over to Google Chrome, because it is such a fast and responsive browser. I have found one or two issues when using Facebook with Chrome, but other than that its a pretty cool browser. The thing I dislike the most about Firefox is that its process does not terminate completely sometimes, and if you start a new instance of the browser the OS complains that Firefox is still running. Even IE is way quicker than Firefox. I used Firefox for development, and specifically the Firebug and Web Developer plugins, but I have decided to switch over to Chrome, because it does have a developer plugin. IE 8 also has a developer plugin. Thats my two cents for now.