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

Code Contracts and Parallel Extensions. Neither are language features (which is mostly what I get interested in usually) but both have the potential to significantly change how we write code.

The DLR does sound cool and interesting, but I'm not sure I'd end up using it much, at least in terms of interoperating with IronRuby/IronPython. It'll be nice to be able to use late binding to reduce reflection boilerplate code though

In terms of C# 4 language features, covariance and contravariance will be more of a "phew, that reduces an annoyance" than a "wahay, cool stuff!" but optional/named arguments could be very handy. It'll make writing/using immutable types slightly easier, although I'd still like built-in support for the builder pattern :)