Right now, Terminal services would have to be my most anticipated feature (role?)
And although I don't really have a use for it, I love the idea of Server core + RODC.
Recently, I've started playing with Terminal Services quite a bit since the release of RC1 and it has become my new best friend. The component of TS that really sales it for me has to be TS Web Access as it has made it incredibly simple to quickly deploy an application that my users can access via a familiar browser based experience. Great stuff indeed!
+Josh