Microsoft programs are so full of holes and there are many talented people out there capable of exploiting these holes however twisted their reasons may be. No matter how many patches Microsoft comes out with, there is always someone more crafty out there to find another way in.
Is it likely your system will be hacked by some vicious email or script embedded in a web page, no (for the record I offer no protection from Weasel)
@Mods: I was going to put this link in the tech support forum but I thought more people would see it here.
I'm on a mailing list for Microsoft product security and functionality updates. As they release them, I get notified. Any updates applying to products that transcend the workplace to the home market, I'd be happy to continue to post them.
Cheers.