Water, its the stuff of life.
3DSMax and PS as usual, the ice terrain was rendered with subsurface scattering, extremely processor intensive but well worth it. With global radiosity for added realism.
The planets maps were done in PS and rendered within the same scene in Max, the shaded lower half of the planet is actually picking up light from the terrain because of where it was actually placed in the scene, though if i got everything right it should look further out in this finished version.
Actual size 3840x1200.