I have a ground tile for which I use a normal map, it reacts good when facing light, but looking in the Sun lamp direction kills the lightning. I'm using nodes, have a look at the pictures. Can somebody tell me what's wrong with my setup ? (connecting the texture normal output straight to the material gives the same result)
Normal mapping is a real pain in the node editor. In fact, it's an open bug. I seem to recall a few months ago someone mentioned/made a new node to fix this, but I haven't seen it in official builds yet.
The way around it I sometimes use (it's computationally expensive and a pain to set up), is to create a material for each normal map. Then you can take the normal output from the material and mix that together: Sorry for not mentioning this in my comment earlier.
You could try advanced material node. This can be found under the input menu. Otherwise you could just add the normal map in the texture panel and enable normal map at the bottom.