I recently went to a session at Microsoft Belgium for ISV's, where Tim Sneath gave a packed session about WPF, answering some question but mainly giving a wealth of pointers of the WPF related information out there. Enjoy!
WPF/Silverlight reference applications
NBC Olympics in Silverlight (Tim showed a demo but it was local on his machine - don't think it is publicly available as the time of this writing)
Hard rock memorabilia (Tim also showed an application for actually making the deep zoom effect that you can see on the site, I guess it's included when with Silverlight 2 somehow?)
WPF controls and dev tools
Kaxaml (XamlPad, but better)
Blendables (the only link in this list which is not free, but some nice samples in the blog, so worthwhile to visit even if you're not spending)
Did you know that an .xps file is actually just a zip file with various files in them, and that one of those files contains a xaml dialect? This is really cool to export clip art from office. Tim just took a random Office piece of clip art, printed it to xps, renamed the file extension to .zip, unpack and pasted a part of one of the files in XamlPad. One or two adjustments for fonts later, and the clip art displayed in XamlPad. Nice to keep in mind!