The sharp edges are really hurting you here. Adding a chamfer to the edges of your geometry would really help things out....get rid of those sharp edges and help pick up some corner highlights. Also some dirt maps added to your textures so things don't look too 'perfect'. Both will help you render not look so 'computery'. Also looks like you have a light ray coming in from the top left, though the shadows on the house say the sun is above to the right.