What a lot of people seem to be missing is that the HTML5/JS crap is for UI - it isn't, and can't be, used for real app development. Just as with conventional web development, where the UI has to be based in HTML and JavaScript (which, we all know, we use because we have to, not because it's a good platform), your server-side language of choice is still doing the real work.
Even in the exceedingly unlikely event that Winforms and WPF are depracated, .NET is still going to be the real workhorse of any application that's not built in C++. .NET is embedded in the industry as a whole - the vast majority of Windows software is built in a .NET language these days, and the vast majority of software written is for Windows. Even Microsoft's products rely heavily upon the framework - for instance, the entire VS2010 UI is WPF.
This reminds me of the guy I sat in a meeting with two years ago who claimed that using stored procedures was stupid because MS was removing support from SQL Server.
Yeah - not bloody likely.
Gotta love the trolls.