Appears as if they're trying to put Resharper out of business to me, with the new call hierarchy window.
Also you can navigate direct to methods from solution explorer.
The default colour scheme for the Dark theme, from tool, options setting, is a black coding window. With the light scheme, the coding window returns back to the default colours that most use out of the box with older versions of VS.
New generate dependency graph for solution option under the Architecture. Great idea in theory, in practice it takes ages to complete, even for a small one method console application. Could be useful though if you have a large project that you're getting to grips with, only if you have the time to run it though.
Appears that Code review support, is very integral in the new VS 11 IDE as well.