...mission is in progress, great maps helps greatly! ;} ...real FLAT EARTH maps are missing though, no ANTARCTICA maps either.
GMap.NET is great and Powerful, Free, cross platform, open source .NET control. Enable use routing, geocoding, directions and maps from Coogle, Yahoo!, Bing, OpenStreetMap, ArcGIS, Pergo, SigPac, Yendux, Mapy.cz, Maps.lt, iKarte.lv, NearMap, OviMap, CloudMade, WikiMapia, MapQuest in Windows Forms & Presentation, supports caching and runs on windows mobile!