Check out these cool mashup applications from Thirteen23 that take advantage of the Windows Presentation Foundation on Windows Vista. These applications also work on Windows XP, but you'll need to install the .NET 3.0 Framework first.
The Nostalgia application lets you connect to Flickr and browse photos through really rich interface. This application shows the user experience possibilities when you blur the line between what is on the desktop and what is online.
If you don't have time to try them out, Scoble has a good video of them here.