My solution is to create various profiles for my different browsing needs. I have my "webdev" profile which has a lot of web development extensions including firebug, I also have my "main" profile for most browsing, the "wastetime" profile and some other profiles.
While my main profile is open most of the time, I can open webdev using "firefox -profileManager -no-remote" for some javascript debugging and close it when I am done without messing with my other open profiles. If I get bored I might fire up "wastetime" to browse some websites, or the "noextensions" profile to check a website with no extensions (sometimes noscript, better privacy, adblock plus, ghostery or even pentadactyl might mess up some website that I visit).
A really cool bonus is that with each profile I can save the opened tabs, so for example I have a "coursera" profile and it has all the tabs I need for the course I am taking (functional programming with scala). So, when I am studying I only need to open that profile either by itself or in addition to other profiles.
While my main profile is open most of the time, I can open webdev using "firefox -profileManager -no-remote" for some javascript debugging and close it when I am done without messing with my other open profiles. If I get bored I might fire up "wastetime" to browse some websites, or the "noextensions" profile to check a website with no extensions (sometimes noscript, better privacy, adblock plus, ghostery or even pentadactyl might mess up some website that I visit).
A really cool bonus is that with each profile I can save the opened tabs, so for example I have a "coursera" profile and it has all the tabs I need for the course I am taking (functional programming with scala). So, when I am studying I only need to open that profile either by itself or in addition to other profiles.