What features are people looking forward to in .Net 4.0 - 4.1

Question

I am very interested in learning what features people are interested in in the forthcoming .net framework(s)?

Whether these be new classes or new controls I am curio

Answer 1

• Optional parameters in C#

More so than than .NET 4.0, I'm really looking forward to Visual Studio 2010, same as jirwin's response.