I've been a loyal Firefox user for quite a bit, but I completely agree with Peter Torr when he criticize Firefox secuirty problems.
He sums it up very nicely:
·Installing Firefox requires downloading an unsigned binary from a random web server
·Installing unsigned extensions is the default action in the Extensions dialog
·There is no way to check the signature on downloaded program files
·There is no obvious way to turn off plug-ins once they are installed
·There is an easy way to bypass the "This might be a virus" dialog