I've just installed the closed source Google Toolbar extension which is now available for Firefox. The auto-suggest feature is quite nice. It gives you realtime feedback on words you could use in your query and how many results they could give. This makes refining your search very easy. Of course there is a potential privacy issue although if I'm honest Google probably know more about me than I do.I should see how much functionality is replicated by the Googlebar which is an open source version. Unfortunately it won't install at the moment however Google's own bar is pretty slick.