I ran across an interesting post and interview on the MS Data Center Blog on the infrastructure architecture aspects of the new Microsoft datacenters. If you are in the infrastructure world, it is worth a read.

The goal of Gen 4 is to modularize not only the server and storage components, which a number of companies are already doing, but also to modularize the infrastructure, namely the electrical and mechanical systems.  The real innovation is around the commonality, manufacturing, supply chain and integration of these modules to provide a plug-and-play infrastructure along with modularized server environments.  In addition, it is focused on scaling the infrastructure with the business demands, smoothing capital investment, and driving costs down as shown by the following chart.

More on MS Data Center Blog:

http://blogs.technet.com/msdatacenters/archive/2008/12/08/microsoft-s-generation-4-data-center-vision-the-architects-perspective.aspx