The top percentage of people in every country is of course going to be attractive. Here's my ranking of attractive from most to least in asia. Keep in mind this is "on average". A fat ass or ugly person in that country is not going to surpass the attractive person in another country.

1. Korean
2. Japanese
3. Northern china
4. Vietnamese
5. Singapo
6. thai, southern chinese, mongolia etc. Basically all the southern states.

Seem like on average, northern countries tends to produce more attractive people, become richer, more powerful etc than southern countries. Take a look at this on a global scale, you will find this is true throughout history on average.