Have you tried Firefox 3 yet? It's still only a beta at this point, but it's coming along steadily reports Mike Gunderloy over on Webworkerdaily. In my own experience, the browser isn't ready for constant use yet, because of some remaining bugs and problems working with extensions. Mike has also identified some significant bugs, but he has good things to say about Firefox 3's performance, which is the area where I've been most impressed with it. If you've stayed on top of the memory usage issues, you'll also be interested. Check his post out.