I work in the IT industry, and this gives me a fairly jaundiced view of Micro$oft's products and practices. However a little reflection on the currently raging "MSblast/Love You San/whatever name it's now using" worm leads me to think that this one shouldn't be blamed on Billy Gates's boys. Yes, the worm exploits a Windows security hole, but there's been a MS patch available for at least a couple of weeks now. Apply it, keep your antivirus product up to date and , regardless of whether you use broadband or dial-up, use a firewall of some kind and you need not worry.
There's actually a very useful article on The Microsoft website about this - you can see it here.