I think this is a very easy function.  But I have been jumping around all over the ESRI site trying to find a solution.
I would like to create very basic thematic maps.  I have seen these maps referred to as "density maps" and "Heat Maps".  I have data on continents,country, state/region, city, etc.  So when you view the map the areas with the higher data values have deeper colors.
I don't need any level of detail on the maps (e.g. rivers, topography, capitals, streets).  But just have it colored according to its data value.  
Are there any examples of this?