.Net native code compilation, aka static linking for the .net age. This feature is a LOOOOONG time coming, they should have had it available a decade ago.

P.S. Mark my words, this is going to be a huge deal. Especially since MS is acquiring Xamarin, which basically does the same thing, but for mobile platforms. With the ability to develop in .net languages and still deliver a plain-jane .exe that doesn't require jitting it'll open up a lot of new opportunities. Especially if they start targeting non-windows platforms like linux, iOS, and android with fully-baked tools. Imagine how much more popular C# would be if it wasn't tied to the Windows platform? And if you could choose whether or not you wanted to ship a small managed exe or a fat native exe that launched quickly?