WPF with Windows 8

You'll still be able to build a 'traditional' desktop application using WPF (or, for that matter, Windows Forms) in Windows 8.

XAML (though not WPF as such) will also be needed to build a Metro app using either .NET or C++/CX. 

My personal view is that the Metro UI is not really suitable for complex multi-form applications and so I think that Mamta is correct that WPF will remain relevant even if the focus (at least initially) will be on building Metro apps.