http://www.opera.com/I was starting to get tired of firefox's little bugs -- like memory leaks and the fact that it never seems to close when I close it -- I have to kill it with task manager. Also the fact that when I restore it, it takes forever to come back up and thrashes the hard drive for a couple minutes, even on fast machines with plenty of memory.
I finally gave up and started using Opera. Conveniently, shortly after I started using it, it became free. While it doesn't appear to be as customizeable as firefox, it's
so much faster! The only thing it lacks is a good adblock extension like firefox had. Putting up with ads is worth it, though, for the huge speed boost and smaller memory footprint, in my opinion.