Song Kang Ho
You didn’t ask, but I am going to tell you.
Song Kang Ho is my favorite Korean actor, although that is not the most vigorously contested category I can think of. He has range and charm and a certain je ne sais quoi that I find endearing. A few of his movies are worthwhile invesments. My personal favorite is Memories of Murder, a review of which can be found at http://www.imdb.com/title/tt0353969/.
A good deal of his movies are available on Netflix.