WorldWide Telescope stitches together high resolution images from the Hubble Space Telescope, the Chandra X-Ray Observatory Center and the Sloan Digital Sky Survey amongst others. The user can choose to boldly go where no man has gone before or follow one of the many guided tours offered by astronomers and academics.
The idea for WorldWide Telescope came from the pre Web 2.0 Sky Server, which was developed by Microsoft researcher Jim Gray. Microsoft's chairman Bill Gates has described WorldWide Telescope as 'a powerful tool for science and education that makes it possible for everyone to explore the universe.' If you're still not convinced check out the preview video below and then make your own mind up.
Microsoft Research Worldwide Telescope