I'm surprised that nobody has mentioned the most critical part of designing a data center: security. The amount of money involved dictates that all details on a data center be closely guarded. Think about the income from ads for Google or selling music on iTunes. Or retailers like eBay or Amazon. Thus information on data centers are the crown jewels for these companies. No way are they going to share this information. The secrecy has reached a point that they will not even acknowledge what country that many of these centers are in, let alone what building. Most have reached the point the military took years ago: no hardware is ever returned to a vendor for repair. It is destroyed on site, never returned for warrenty. Setting up a large data warehouse is a dark arcane science limited to a select few engineers. And the world of the cloud computing will take this secret keeping to another level of paranoia. Billy Pettit