No. We run on hardware designed specifically to be used as servers.
While there is nothing wrong with desktop hardware, it is not suited for the tasks we put it through and desktop hardware takes up far too much space in a data center to justify the cost savings.
Each one of our servers are hand optimized. We do not like the idea of using generic disk images to roll out new servers, and we're small enough to be able to tweak each server to get the maximum performance out of it.