There is an interesting tendency visible on ITJobsWatch regarding Windows Presentation Foundation. It's that the demand for WPF workforce has grown significantly in the past 6 months (as of 2008Q2). I don't really got around peeking into the actual job descriptions there but three quarters of a year has grown the demand for WPF-developer up to 1,2%. Compare this do WinForms' (plumetting) 3,9% you may wonder if WPF is really ready to replace WinForms or maybe it has so many pioneering features that it generates a whole lot of new expectations about user interfaces. I must say that I Don't Thnik So. Of course I'm biased towards Line Of Business applications, I'm really hesitant about WPF when it comes to LOB because I can't really believe that people won't miss WinForm's DataGridView, the tabbed interfaces, the Masked Textbox or the MDI. No sir. It's true that there has been a lot of debate on WPF LOB usage and WPF vs. Winforms and WPF credibility and a lot of promoting of WPF (albeit some spectators say not enough of it) from Microsoft, and I believe that WPF is still sorrounded by a lot of FUD, and I don't really want to name the guilty parties. Let me just highlight one of the highlight featues of WPF-based development: the fact that designers can work more closely with programmers on a WPF project. I can't see why and how this could be a very big achievement in a time where people have learned that designers don't give a heck about functionality and programmer's don't give a heck about user interface design. Not because they are evil, simply because there is a whole impendance mismatch between being the designer-world and the developer-world (and the software usability world before we forget what the game is about) so unless you can spend a lot of money on designing and usability testing your user interface, you're effectively busted. And if you're really busted, it doesn't make too much of a difference which technology you actually use.
Of course there's a lot of value in WPF which has soon to be explored, but I think that we're not there yet. It's really cool tho to have a framework which encourages separation of concerns in an area really really prone to produce ugly and smelly code.