[Osiris]

Wasn't one of the points of the .NET Framework to make architecture independent apps? The CLR is compiled to the native instruction set, but apps are only compiled to IL and thus are dynamically recompiled to the native instruction set.

So, ideally, you'd just have one download.

[xorxornop]

And this is exactly how it works with Windows Store apps. You upload .NET bytecode, and the Store delivers the correct compiled-to-native code for the user's architecture.

You can also make fat packages, if you don't wanna distribute through the store.

[raverbashing]

Yes. It is promoted strongly inside MS, however it seems it is not much used by them.