Ars Technica reports that multicore processors and virtualisation will see the (physical) server market shrink. (Not actually a reduction in the number of servers, mind you, but a slowing of growth from 61% over 3 years to 39%).
Turns out this could be good for the planet. As Treehugger says, virtualisation is a good way to green your servers by not over-providing for occasional peak processing loads. Makes sense, especially if the stats are right: that most servers only run at a load of 5-12%, but burn hundreds of dollars worth of power every month.