Just read some reviews on Intel's newest Zeon processor. Looks like the increase in processing power over prior versions and the competition is a very substantial jump… like double. Just as big is the increased support for virtualization to take advantage of features in Windows Server 2008.
Doubling the processing power while reducing or keeping steady the power consumption is significant.
We are hosting some client applications at Q9 Networks. They charge for power and bandwidth. If I can cut my power consumption in half to get the same work done, that would give us a substantial power cost reduction. Might even pay for a couple of servers in year.
Now if we can just get past the physical limitations of hard drives at a decent price point….