First of all - beauty lies in the eyes of the beholder. So, the concept of beauty is very relative.
However, if u keep the philosophical debate out and look only from the perspective of instinctive male opinion, I think a voluptuous woman looks much appealing. The male brain predominantly is turned on by curves, although there would be variations in the level liking depending on individuals.
One shudnt be fat, but then being skinny is equally horrific. A curvy woman looks much better than a skinny, emaciated, anorexic one, who appears more stick-like accentuated with pointed shoulder bones.
People confuse between being slim and thin. One can still be curvy and slim, through a healthy diet and exercise. But some "health-freaks" go on a pure diet, skipping meals without exercise and become lanky and frail. Most of the "modern" models look so.
In summary, keeping philosophical debates out, the first liking would be for a voluptuous woman, rather than a pale and skinny one. I am yet to see a magnificent artistic masterpiece of some painter/sculptor which depicts an anorexic woman; almost all the works are those of gorgeouly curvy women.
