There are currently several sites I visit regularly -- as part of work, mind, so these are professional business sites not bleeding edge web geek blogs -- that will crash Firefox.
Have you filed bug reports for those crashes? Care to share more information about the websites that cause them?
I'm serious, I can try to help get those bugs resolved.
"If you own a machine, you are in turn owned by it, and spend your time serving it..." -- Marion Zimmer Bradley, _The Forbidden Tower_