ArcExplorer

Check out ArcExplorer - the website, a flash version of the application, and a downloadable version. It's similar to GoogleEarth but allows you to also view data themes overlayed on the map (e.g. the census data, etc.). Looks like there are a few problems too -- like the projection is clearly bias towards USA so if you zoom in on Europe the countries look squished. Anyway, it has potentials... OH, it's FREE. (surprise surprise!)