Looking at Blue Sky Thinkers post, I use Firefox Portable, works fine on my laptop and also will run directly from a USB stick and not leave any remains behind. You can use it anywhere, like an internet cafe and nothing stays behind when you unplug it.
All you need to do to back the whole lot up is copy the Firefox Portable File wholesale and you have a backup of everything. You can even download, email software, media players and anti-virus software now.