WPF is dead. Silverlight is dead. You should be moving to HTML/JS already. Hold on a second! A great argument for .Net.
In my opinion, even Silverlight is not dead. Silverlight is good for LOB applications. Till the number of HTML 5 developers reaches a critical mass, and till HTML5 is fully cross-browser compatible, and till previous versions of IE is shelfed out, Metro apps written in HTML 5 will not make much sense.
If I write a metroapp in WPF/XAML, can it run on Android based tablets? Are there any cross platform plugins available?
These are the questions that Microsoft needs to answer before we decide whether to invest fully in .Net, or a hybrid approach.