The new ESRI Resource Centers provide content, web help, and support for users of serveral ESRI tools, including ArcGIS Desktop.  Content for ArcGIS includes maps, layers, globes, and globe layers.  Much of this content is provided by ArcGIS Online as free services.  Including:

 
World Imagery


Description


 World Street Map


Description


 World Shaded Relief


Description


 World Physical Map


Description