if you think your graphics card can handle it, try using these images to get more detail
http://www.oera.net/How2/PlanetTexs/..._2500x1250.jpg
http://www.oera.net/How2/PlanetTexs/..._2500x1250.jpg
you have to resize them to 2048x1024 and convert to bmp and put in the same folder where the proggy is.
and there are some more here:
http://www.oera.net/How2/TextureMaps.htm