Firefox is done. You should upgrade if you are using this browser. I did some trials last week because of the Maxthon/Google Toolbar issue and found that while Firefox is a very nice browser the plugins leave at lot to be desired. They include conflicting functionality and have bugs.
Maxthon just works the way I like it and it stays for the time being my browser of choice.
Check out the Firefox release notes while you wait for the download to complete.
Disclaimer The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.