I've been starting to learn WPF for 6 months now. I'm stuck a bit in this study process as first of all in our company we have not had yet any project where we could use WPF.
Another reason why I was stuck was a bit because of books, so far I had following WPF books on my bookshelf:
Professional WPF Programming (Wrox, Chris Andrade et al)
Windows Presentation Foundation Unleashed (Sams, Adam Nathan)
Both books are not bad at all, but somehow I was having quite alienated feeling while reading them.
My common feeling from reading of Adam Nathan's books (Com Interop, WPF Unleashed, Silverlight Unleashed), is that I'm reading quite comprehensive and very nicely formatted/pictured Encyclopedia. Reading encyclopedias can be a good exercise, but in case of WPF I would not consider it to be the best first step to do.
Professional WPF Programming from Wrox is quite inconsistent for my type of programmer, because it looks like guys tried to write the book that would be have same value for the "creative UI" and core developers, while it may be important at some stage to see the WPF world by the "creative UI" developer eyes, it is not he best starting point for me.
And now, finally I got into the book which is making the trick of "being it" for me:
Programming WPF (O'Reilly, Chris Sells & Ian Griffiths)
The book is in its second edition now which proves something, and is pretty actual.
I'm absolutely enjoying the style of the book and the way information is provided. I'm typing/running my versions of the code they provide as I read and feeling finally well about the process of getting into the new technology.
It used to be Wrox 5 or so years ago to me, but now my credit goes to O'Reilly with series of books I consider to be the best in the field:
Programming WCF Services, Programming Windows Workflow Foundation, and now Programming WPF.