Further reinforcement lies in the news that Microsoft's defensive measures in some versions of IE have been found vulnerable themselves.
The vulnerability, exploited in recent attacks on Google and other companies,has gotten a lot of press, as much for the role it played in recent Chinese exploits as for its nature.
That nature can give hackers remote execution access to compromised systems.
Microsoft's advance advisory notice on the patch is here.
Technical details on the patch are here.
Getting the patch deployed to all of your systems -- and the systems of employees who work from home or on non-company equipment -- is in your hands.
Patch 'em up!