Thanks this looks a lot better really, but somehow I still have the feeling it should be done differently.
I want lights to really AFFECT my terrain I really have no clue at all about how I should do this.

Like for example sunlight. I set my sunlight in such a way that it lights my house like it would do on a sunny afternoon/evening. And really, the lighting on the house looks great (well for a simple house it does). But the terrain still stays the same.
