firebug

When installing Ubuntu on one of the new machines we get from time to time, there's a common mechanism I repeat over and over with Firefox:

1. install the Firebug extension
2. install the Web Developer extension
3. install the ShowIP extension
4. install the GooglePreview extension
5. change the link of the start bar icon to start Firefox, to "firefox -no-remote -ProfileManager %u" instead of "firefox %u"

The latest option allows you to launch Firefox using different profiles, each of them having its own extensions.