Ian Griffiths and Chris Sells, authors of the book Programming Windows Presentation Framework, have posted a great article up on MSDN.
The article is called "Top Ten UI Development Breakthroughs In Windows Presentation Foundation," but Chris says that he'd rather have called it "Ten Things That Would Surprise You when Learning WPF."
Either way, there's something in there for everyone.
P.S. Did I mention that the December CTP of WinFX works with the Release version of Visual Studio 2005?!