Even before C#2.0 is out (RTM) we already have some sneek preview of the C#3.0 features. Check out Cyrus's blog on this. Some time back I had said to some folks here that with some powerful functional programming fans :) in MS we are surely going to see some functional programming features creep into C#. Anonymous methods (lexical closure), continuation (yes I know in very limited format) got into 2.0 and now we have lambda expressions in 3.0.
However I had expected more features from Spec# like contract verification and checked exception to have been introduced. Maybe they will be.