oh and the render looks like that the shadow casting light is the only light in the scene. you could use a simple 3 point lighting (watch mikes tut) - or the quick fix is to have the one shadow casting light and add a ambient light with low intensity.

and that is also a good idea - on day you should spend and take a model (which you done before on another day) and just 3 point light it nice as excercise. if you want it a tough thing - do not use texturing, only a simple lambert and make it look good with 3 lights only ...