Korean music recommendations?

[Melodie]

Since many of you seem to enjoy K-Pop, I figured it's the best place to ask.
I have been watching Korean movies lately, and it made me want to discover some of their music.
I know who BoA is, and all those other boy/girl bands that have threads all over this place. I'm looking for something with more depth, and preferably someone who writes his/her own songs. Any genre will do