These are the most attractive Korean idol singers/dancers, to my eyes. Although beauty lies in the eye of the beholder, physical attractiveness tends to be largely universal. My "universal" ideal of beauty comprises large expressive eyes, fair skin tone, relatively small features like mouths and chins, defined nasal bridges and pointed noses, and long and lithe bodies. It is noted that although these selections are largely based on physical appearance, their 'branded' or perceived personalities (interviews, behind-the-scene videos, variety show appearances, etc) also weighed heavily. This list will, hopefully, constantly evolve as new talents make their entries.
Joo-yeon of After School defines the beauty ideal -- small face, large eyes, and angular nose and jawlines. Perfect facial proportions... the Kpop Helen of Troy. An effervescent jokester with a boisterous laugh.
Suzy of miss A features a baby face. Straight bangs perfectly complement her features see more on Suzy
Yoona of SNSD, the "doe face" -- the standard for symmetry, proportions works with any hairstyle see more on Im Yoona