Where I worked, each employee got a what was essentially a dumb terminal that provided a virtual Windows environment on a central server. The processes were shared, so only as many instances of Windows were created as happened to be logged on. You were assigned a certain amount of disk space on central storage.
Naturally, you were not allowed to install or change any software, or remove any data. It was very secure. You could log on from home and get the same virtual desktop remotely in your browser.
Virtualization is a big part of the move to BYOD, and to giving users their choice of hardware platforms. A lot of companies put their core business apps and documents in a virtual machine, and leave things like messaging, e-mail and Web browsing -- and things like social networking in downtime, which isn't central to business, but keeps morale up -- local. That is where choice of platform becomes mostly irrelevant to the company, and user preference can be indulged (again, good for morale).
I used to work at a Web publisher that had its CMS in a virtual machine and things like Photoshop -- which would put a lot of strain on server resources and network speed to make it usably responsive -- local to the user.