Hey Lostclimate,
try to reduce the lights a bit its a bit to strong.
Maybe add a "hemi" light to get more atmosphere.
Maybe change the Light color to an"warm Yeallow" ?!
At the last Picture:
Please remove this green "dirt" (?) it looks wrong to me (Color is to strong in my opinion).

regards Sebastian

[Blender]Terrain creation ENG/GER
[Blender]Low Poly Tree Modeling
[GIMP]Create a Texture for Terrains