Since I upgraded to firefox 7 my firefox seems to crash when on a page with any form of flash, though it doesn't happen every time. When it does, I have to start a new session as it'll just crash again otherwise. I've gone through my about:config changes and don't see something I've done. This problem started on the 11th October, and persisted to the 13th. It stopped when I purged Flash, reinstalled, and disabled hardware acceleration, but returned on the 17th. During this gap I upgraded from xubuntu 11.04 to 11.10.