I was never a fan of the first version of the Google Firefox toolbar. It just took too much screen real estate for the functionality that I used. However the latest version just provides a palette of options that you can pick and choose from, so now I'm happy! I also hide the usual toolbar and drag the location bar up into the menu bar, this leaves much more screen real estate for web page content. Above is what my Firefox looks like at work under Linux, at home I use a Apple Powerbook and you can't move the location bar on that (which is kinda annoying).
Also notice that my window manager doesn't have any title bars (to save space too) I'm thinking about switching to a new window manager (away from mwm) but haven't yet done so. I'm looking for something like Apple OSX's window manager that steals focus ONLY when the transient window is spawned by the current active application.