I'm of the opinion that it makes no difference whatsoever. Beauty imo is the result of general physical fitness, health of skin (ie. no spots, scars or sun damage) and attitude which manifests itself in a range of areas which people instinctively pick up on like facial expressions, body language and manner of speaking.
People will generally find happy, physically healthy people attractive regardless of petty factors like breast size, weight, body type, skin colour or hair colour- as long as we don't go into extremes. Individuals will find different things more attractive than others, but in the real world I doubt you would find many people who will *only* go for someone who has one set of physical characteristics.
Of course, I have no romantic experience whatsoever (Star Trek & HOI2 are social vices), so I could be wrong.