Well, this is a great conversation here. WPF is no where even close to replacing WinForms. WPF is great for creating high-graphics type of interfaces. But if you have tried to create a dialog with very many data entry controls, you know that WPF would make end-users want to commit suicide!WPF is still a generation or two away from being even a remotely decent replacement for WinForms. There are a lot of things that I really like about WPF and am excited about (i.e. the rendering dispatch thread). We recently had a very long debate about one of our future medical products which is very graphically intensive and whether we would use WPF or WinForms. We landed on WinForms and GDI+. The meshing of WinForms and WPF is like oil and water (think combining a web control in a WinForms app and then making the web portion and the WinForms portions work together....that it the level of frustation you will have).
But the straw the pushed us over on this debate came down to the PropertyGrid. We have the need to allow our end-users to create and customize screens so we will create a designer for them to use. Well, WinForms supports a run-time PropertyGrid...not WPF. So all of the wonderful type editors, etc. that you create you would have to create your own PropertyGrid. Secondly, XAML is a horrible platform. You can do a lot in code, but there are times when you must use XAML...another major downer of WPF.
Regardless of what you hear, WinForms has another 10-15 life...easy! There is way too much money and momentum in WInForms to go away any time soon and WPF is in its infant stage of coming into the marketplace. So my advice would be to stay away from creating any type of data applications in WPF.