One of the big pushes in Server 2012 is the use a Server Core installation instead of the full GUI install. Microsoft have put a lot of effort into encouraging administrators to use PowerShell as a core tool for day to day administration of servers, which is why is seems a bit strange that a Server Core installation boots to a traditional command prompt instead of a PowerShell prompt. To change your Server Core installation to launch PowerShell instead of the normal Command Prompt is a simple registry change.