I'd have to say this is pretty exciting stuff from Microsoft. Examples of implementation of SharePoint components using Silverlight! The most impressive blueprint is the social networking tool which sources its information from the User Profile that is ultimately imported from AD.
Impressive because, it surfaces the information in a very intuitive UI, and not only that, it also links back to the user's public "My Profile" page.
For more information, the Silverlight Blueprint for SharePoint site is: