Apart from google maps
Can use web map services from ESRI. They have a silver light extension to display ESRI and Microsoft map services.
Virtual Earth has an javascript control to display maps which can be interact from code behind and mashup with data
<script src="http://dev.virtualearth.net/mapcontrol/mapcontrol.ashx?v=6.2"
type="text/javascript"></script>
<script src="/Scripts/Map.js" type="text/javascript"></script>
for stand alone maps, can use SVG map which is a scalable vector display from adobe.