I don't see WPF as being dead, even though the Web had taken precedence lately there still a big market for desktop applications obviously. I haven't done a desktop application project since WPF was released the last desktop application I built was WinForms but if I had one come up I would look no further than WPF.
I fear more for Silverlight to be honest as I would always look to use standard HTML + JS before even considering a Silverlight app and I think RIAs have their place but it all feels a little Active X to me, I dunno if Silverlight will still have much love in 5 years time, especially when HTML5 becomes the standard. I mean look at when SL got the most attention, wasn't it the whole streaming media thing?
I haven't come across many SL business applications and I certainly haven't had any clients request a project that would warrant it but that's just in my own small world of experience.
Maybe I'm wrong but the whole RIA thing to me just doesn't feel right, I've refrained from putting too much effort into WPF and Silverlight yet bar reading a few books.
I've managed to be able to judge quite well where to spend my effort on technologies in the past so I'm just following my gut feeling at the moment. But this is IT so who knows!