EarthDesk is a Mac program that displays real-time wallpapers and screensavers on your desktop showing the Globe. The application lets you choose from a wide variety of projections and map models, shows real-time moon and sun shading, and provides you with very simple-to-configure display settings.
After you install this utility on your Mac, a file named EarthDesk.prefPane will be added to your Applications folder. So, EarthDesk won't give you access to an individual interface; instead, it will add a new panel to your System Preferences app from where you can change the way EarthDesk operates. The app will let you change the projection style (Equirectangular, Mercator, Sinusodial, etc.), select the proper centering options (which are to be displayed in the middle of the map; for example, it can be a city or Sublunar point), and choose the preferred map type (Natural Color, Political, Living Earth Satellite or Shaded Relief).
You can also enable the Show EarthDesk Menu Control option. This way, you can change the application's options from your Menu Bar by selecting the proper display settings.
In my testing, the program worked flawlessly, without slowing down the performance of my Mac. What's more, it immediately applied map settings changes and updated map representations.
Briefly, I think it's worth buying this application if you got bored of your desktop and wish to change its appearance with a stunning Earth map representation.