Just a heads up for the FF user community.
The backgroud downloading / autoupdate seems to be working well.. No sooner had I seen this post I notice FF was asking me if I wanted to install the update it had already downloaded.
Another reason to make the upgrade, next to just upgrading to be most current:
http://www.us-cert.gov/cas/techalerts/TA06-153A.html (http://www.us-cert.gov/cas/techalerts/TA06-153A.html)