Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Disable all of your extensions and then close and restart Firefox. Then re-enable them one by one, and see if it starts crashing when you enable one of them.

There are a few extensions that cause problems in Firefox 2.0 (All-in-one Gestures, among others). This doesn't mean there's a problem with Firefox. Rolling back is asinine.
 
Disable all of your extensions and then close and restart Firefox. Then re-enable them one by one, and see if it starts crashing when you enable one of them.

There are a few extensions that cause problems in Firefox 2.0 (All-in-one Gestures, among others). This doesn't mean there's a problem with Firefox. Rolling back is asinine.

It does seem that way since I've got a nightly (more error prone usually) version and it's not crashing at all. Even the quirkiest web pages seem to keep going, though they might not look like IE 7 rendered them.
 
Just installed 2.0.0.1 and reinstalled the toolbar. So far so good, but 20 minutes of crash free operation is hardly what I call a success. I'll keep testing and let you all know. Hopefully this will fix the problem once and for all.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.