I haven't used WPF in a real project, just played with to learn the new stuff. My 2 cents is to pick up a book. A good book can help overcome the deep learning curve with WPF. I bought a book called WPF unleashed, and I think it's worth the money(By the way, I didn't need a book to pick up Win Form). When I finished the book, I feel WPF is not as bad as I thought before. For XMAL, I think it should be treated as "Programing Language", not just a markup language to define the user interface. It's as important as C# in the WPF world in my opinion.

It seems that Adobe AIR is a pretty hot topic lately. I like the idea of having a universal runtime to run a desktop application anywhere no matter of OS. What I don't like is AIR uses web programming tool to do that. After all, it's a desktop application not a web one. I am just wondering if AIR is really the right direction for desktop programming.