Tasch - I've always been curious about how many layers you use in a typical work? Do you use several or only a few? I find it hard myself sometimes blending an image with the background if I use too many layers because there are so many elements to deal with, light, color, shadow etc.
I agree with you it's hard to blend nicely if you have too many layers and imo it gets a bit artificial. I normally have a layer for the background, for the main character and then depending on the depth in front and behind the character layer.
I do add new layers if I add and try out things first but I merge them down as soon as I am happy with the outcome.