The SDK controls are now themed in the Windows system color theme style, and the Toolkit controls will be themed very soon! The updated project is available for download here.
For those of you who desire a bit more contrast in the theme, particularly for high contrast color modes, there are a few approaches you can take...
What follows are screen shots of the PDC Ux in default and high contrast white modes and the newly themed SDK controls in various Windows default and high contrast modes...
Tim Heuer has a great blog post on the new NotificationWindow class for Silverlight 4 Out-Of-Browser applications. This class allows you to create notifications or 'Toast' for your Out-Of-Browser applications when you need to provided helpful information to the user as they are interacting with the application.
Tim provides great visuals for the notification window in his sample application, and I decided to leverage his sample to explore things myself and created a style that maps nicely with the default Silverlight control styles. My sample project can be found here and the visuals can be seen below...