I think nothing shows off the power of Vista and WPF (Windows Presentation Foundation) better than this browser application (requires either Vista or XP with the latest .NET 3.0 installed).
Very impressive stuff.
The British Library has digitized the pages of fifteen of their most valuable works and created Turning the Pages, a browser-based WPF application that allows you to interact with these books in a virtual environment from the comfort of your home. You can open a book on your desktop and by clicking on a page, physically turn it in a 3D environment. You can zoom or pan around each of the pages; the page turns themselves are created by modeling the actually deformation of different types of material (for example, a book with vellum pages is far heavier than something printed on paper, so you'll actually see the page start to collapse under its own weight). For certain books, such as the Sherborne Missal, a 15th Century prayer book that is considered by many to be the most magnificent English book from the Middle Ages to have survived the Reformation, you'll see that the gold leaf catches the light as you move the book around. Another really cool aspect of this application is that this project has reunited two of Leonardo Da Vinci's notebooks digitally: you can compare the Codex Leicester (owned by Bill Gates) and the Codex Arundel (part of the British Library's collection) side-by-side.