This is the most impressive WPF (Windows Presentation Foundation) product I have seen. In fact, it may be one of the most well designed RIAs today.

Using Lenses to navigate from one section to another is a incredible interaction pattern that could work for numerous complex applications.

Start at 1:00 minute into the demo to see what they mean by Lenses:

First person user interface/ Immersive experience in the Atlas Lenses:

Nice navigation with maps and nodes in the Topical Lenses. You can interact directly with the screen, select a whole area, then send you selection to another area- check this out at 1:35:

They also have some great filtering and complex filtering patterns, check out the last two links on their product page

Thanks to Bill Scott for showing me this app.