Why you would want to do this...
Much lower TCO.
As a startup CTO I have run IT-less companies with the simple combination of an all Apple desktop network and Google Apps for mail and calendar. Simple, reliable, and on the rare time I have had an equipment failure (always due to external factors such as someone else plugging a machine into a spiky socket without a surge protector) the Apple store has been there with immediate help and replacement.
Now, if you manage an IT department, this could be your worst nightmare. A business network that actually functions well *without* your staff of babysitters.