a few people have mentioned firebird, and i just wanted to aid in the pimping by putting a direct link to the installer. despite that it's still in early realease, i may start recommending it to more of my clients, as to default popup blocking really decreases the likelyhood of the user getting spyware. if you surf more han an hour per day on average, you'll notice the speed benefits as well.
http://downloads.mozdev.org/seb/Mozi....6.1-setup.exe
mozilla-proper is a little bulky for most users, i think.