This article today finally backed up what I have been blogging about which is that Blades (heavily used in Virtualization deployments) are power hogs. So while you just freed up 5,000 sq feet in your data center, you doubled your draw and D'oh! you ran out of power and can't cool the shiny new virtualized environment.
The closing quote in the article:
If new blade servers crash because the data center overheats, that's not very efficient, is it?
Is the least of my worries. How to Justfy a 7 or 8 figure purchase that you can't light up and run key apps on is a bigger problem, no matter how efficient it makes IT.
Glad to see someone else paying attention to this...