My wife used Firefox for years. Last week it automatically updated. Since then it crashes. I have uninstalled and reinstalled it several times but it still crashes. I emailed Mozilla but have received no help. Now she uses Explorer and bitches about how slow it is.
You could consider Safari.
If you haven’t already, look at the Release Notes. There is a wealth of information there including “Known Issues” which covers some of the known problems with Firefox 3.0.7