Trying not to bash Windows here, as I personally think that Windows 7 is a much better operating system than it's predecessors. However, I think this is interesting. I've seen this happen at several companies lately. While Google has been very Mac centric for awhile now, according to friends I have in the company, a conscience effort to move everyone off the platform in such a big company is an interesting effort.
FT.com / Technology - Google ditches Windows on security concerns.