Can't believe that you mentioned Tell Me Something (2000). What an awesome piece of korean horror/thriller. The way they mix those two together is just incredible. It's pity that Hollywood does not succeed at those very often save for Seven, Silence of the lambs and couple of others.
Along the same lines I would recommend The Chaser (2008) and No Mercy (Yongseoneun Eupda) 2010. And already mentioned I Saw The Devil.
Also I have noticed that that generally on this board asian horror does no get too much love and/or respect mostly probably due to its obscurity. Since I am not too sure about forum rules here, I want to ask Mods if it would be OK to do some weekly mini-reviews on well known and some not well known pieces of Asian cinema. All horror of course. Cheers.