You can download Windows Server 2008 RC1 now. Its most interesting new feature is the Group Policy Preferences. Microsoft integrated PolicyMaker in Windows 2008, a tool from DesktopStandard. They acquired this company in 2006. I had a quick look at it today and I must say it is an absolute killer feature.
Group Policy Preferences allow you to configure many more details than with regular Group Policies. I will blog more about it next week.
It seems to me that an RC1 domain controller boots up and also shuts down much faster than under Windows Server 2003. You probably realized that domain controllers usually need quite some time until they are ready to shutdown. The Active Directory database of my test machine did not have much data, though.
It is interesting to note that Windows Server 2008 RC1 is released at the same time as Vista SP1 RC1. Obviously, they are connected. I think, it is predictable that many organizations will deploy Vista SP1 and Windows 2008 together.