Rather than relying on pure javascript to instantiate a Map, which some developers way struggle with, introduce a map control that has server side functions (as well as client side) to select areas, geo-code, and add markers. Add the features contained in http://www.telerik.com/products/wpf/map.aspx

Also, to be able to databind to a collection, specifying a LatitudeDataValue, and LongitudeDataValue and DisplayMemberValue which describes the Lat/Lng and marker names, without the need for client JS! Would love to see the heatmaps implemented in particular.. Any other takers??