Though Windows Server 8 is still beta, it is garnering a lot of attention from the virtualization industry and customers as well. This is due to sheer number of breath taking capabilities packed into it and as well as the abundant savings customers make by using the virtualization capabilities built into it.
For starters see the chart below.
To know more about this please go to http://servervirtualization.cloudapp.net/. There is also a cost savings calculator whereby you can plug your numbers and see the comparison charts.