One of my favorite plugins for Firefox 2 is SearchStatus from quirk.biz.
It sits on the bottom right status bar of Firefox and doesn't get in the way.
Not only that, but it's always there when I need it, and I no longer need to waste precious toolbar space with the Google toolbar - this gives what I need - the Pagerank of all pages visited. Not only that, it gives me the Alexa rating too!
http://www.quirk.biz/searchstatus/
Bye bye Google Toolbar... you won't be missed.