According to a report at the Financial Times web site, Google is supposedly getting rid of Windows in its desktops; new hires need to choose Mac OS X or Linux for new machines.
If true, this is probably the highest-profile Windows phase-out. I don't know if it's true or not – apparently, Google isn't commenting – but if so, it is surprising. Sure, you can run your business on OS X or Linux – it can just be more difficult for a larger company. I am a System Admin for my company, and while I use my Mac laptop every day, I just don't see my company being able to switch over. Microsoft has a lot of tools and programs for managing systems in the enterprise. Apple has some of these tools, but they don't seem to be as extensive. True, many of the Windows tools are unwieldy, but in many cases, I haven't seen good equivalents for OS X (and I don't work with Linux very often).
Apple seems to be more focussed on consumers rather than businesses. Sure, Apple has OS X server, and it is easier to administer for a smaller company than Windows server. But I just don't see the same level of commitment from Apple towards enterprises as Microsoft. Windows server has a very large number of very granular settings for controlling the servers and desktops. Some of it may be overkill, but it's there if you need it.
In addition, Microsoft has a more public roadmap of where they're going than Apple does. Apple is much more secretive, and they really need to be because of their heavy emphasis on the consumer space.
So I'll be curious to see if this is true.