If some one asked whats the most important aspect of a shoot I would have to say lighting! A scenes mood, shape and quality is totally affected by how its lit. I recently attended BVE in London and watched a very informative and entertaining presentation by Johnathon Harrison. It seems the last thing people spend money on yet it has such an impact on the end result. A few lights used effectively can create a stunning look, far more so than the camera or plug ins added in Post.