I have been running FireFox 3.6.3 since April 3, 2010.
I had thought that 3.6.3 was slightly better on hangs than FireFox 3.6.2, and my Windows 7 Reliability History appears to confirm that. I have had one FireFox hang since I installed 3.6.3 — BUT I also recognize that I have not been banging FireFox as hard as I normally do, since I am going through a transition in my work.
Yesterday, or day before, I got an unsolicited ‘pop-up Windows’ from FireFox saying that it had, unilaterally, disabled my Java Deployment Toolkit plugin because it was known to cause instability! Wow.
This is kind of interesting because on March 23, 2010, I had suggested that you upgrade to the latest and greatest Java because I had the feeling that it was Java that was responsible for many of the crashes.
So if YOU are using FireFox 3.6.x … go to TOOLS and invoke ADD-ONS >> Plugins. See if FireFox will tell you to disable Java Deployment Tools. Even if it doesn’t try it.
Maybe it will help.