I saw a reference to this while looking at the new feature list for Firefox 2.0, and decided to give it a shot. I rather like it. It's a plugin for FF 1.5 or later that uses the addressbar as a progress bar for loading a webpage. You don't have to keep an eye on the statusbar to see what's going on. This is similar to how Safari under OSX works. I'm rather liking it.
The plugin is called 'Fission' and is available here.
Ooh, I like that!
Amusingly enough, I got to the same plugin the same way over the weekend. Me like.