This is tough, there are so many hotties! I'll say:
Song Hye Kyo
Jeon Ji Hyun
Kim So Yeon
Go So Young
Kim Hee Sun
Ha Ji Won
Kim Nam Ju
Son Ye Jin
Kim Gyu Ri
Honorable mention goes to (sorry don't know their names!): SHK's best friend in "Hotelier"--(the girl who worked in the toy store)...the sexy secretary in "Guardian Angel", and the "Jennie" character from the series "All-In".
If posters only wish to list 5 names, that fine. This should be interesting!