At my Mix08 session last week, I showed off a FlickrViewr app that I had written. You can search different user’s photos (or search all public photos by leaving the username blank).
updated: This app has been updated for Beta2. All of its controls now use VSM!
updated: This app now uses DevDave’s AnimatingWrapPanel.
updated: Updated for Silverlight 3.
In order to run it on your own, you need to go to flickr and get your own flickr api key.
Special thanks to Pete Blois. I expanded upon his Xml Serialization Flickr library. 
This FlickrViewr application uses:
- Styles
- Control Templates
- UserControls
- Custom Controls
There are also a few re-usable goodies:
- HorizontalWrapPanel (note: the app no longer uses this wrap panel)
- ContinuousProgress control
- ModalDialog
You can grab these separately here.