I agree with Ice-boy about the sunlight.  Unless the angle is steep or an apparent atmospheric disturbance, leave the sunlight white for the moment until you are more comfortable working with lights.  IBL will convey the colors of the image but it is best apparent in the shadow areas of your image.  Be aware that you should try to match your IBL and lights with your scene for a better natural environment.  That is why individuals who use photo backgrounds use the same image to create their IBL.  Also, unless the original IBL image is very dark, you should never have to over blow your light intensity to 100% or over.  Especially if you use Gc material.