For a current project we are using some geotargeting stuff and want to map these geodata to a worldmap.
If you need to find the right position with longitude and latitude on a map, you need a map that is absolutly correct. Otherwise you will have the problem that some places are directly in the water. BAD!
So I looked around and found this post about free vector worldmaps
On additional benefit, you can build zoomable maps in flash with these kind of maps.