I have used FF for since before 1.0 - in that time it has crashed a few times when faced with intensive Javascript or Java, and usually the Extensions of some type. In general - it doesn't crash for me except very rarely. I've used it on XP, Vista, Fedora, SUSE, and Ubuntu linux all with the same result - rock solid stability except with certain extensions.
Granted it really really loves RAM

.
Right now after three hours of use it's consuming 53MB of RAM. Note - I disable many extensions until I need them. So it's lightly extended for everyday use - Greasemonkey, Web Developer, a few others I tend to depend on. Learned a long time ago not to trust too many extensions all loaded at once, and to make damn sure I test each one separately to detect the problem makers (crashing/even more RAM eating).
So, I'm the wrong person to complain to - everytime I hear about crashing, and 200MB RAM vanishing, I assume there's an extension or really long term use involved. I've never experienced problems otherwise. Using 2.0.0.9 here on all systems. I can't believe I'm the only person who has used Firefox for years without any mentionable problems not traceable to a bungled extension or four.