The disruption from Microsoft's failures are only starting to be felt. Check out Frank Hayes' "The Pain Begins " column in the January 26th Computer World.
Corporate IT stubbed Vista. What will it do with Windows 7? And what's the fall-back plan if Windows 7 is bust and Microsoft does an "end-of-life" in Windows XP to force upgrades and purchases?
It won't be pretty. Microsoft will start to lose even more ground. And the open-source OS world will blossom into a dozen competing offerings with complex services, support, help-desk, SaaS add-ons. It will be much more complex.
It will be very disruptive to current ways of working. With a single desktop OS, purchasing is easy. Find a hardware vendor, pick a few items out of a catalog. Buy the same OS for servers, and to claim to be an all-Microsoft shop. People currently (with a straight face) claim they never use open source software (in spite of Apache, Java and Perl).
When Windows is bust, what then?
Every decision will require thinking. That will hurt.