Voted Korean dramas, since they're the ones I watch the most. A close second would be Japanese, but I get my Japanese fill on animes and mangas already. I've watched tons of Japanese and Korean (and a few Taiwanese) dramas that I don't think I should mention all of it in one post. I'm currently watching two Korean dramas, though: Chuno (Slave Hunters), which is a historical drama. It's super action-packed and has great acting and beautiful cinematography. The second is Pasta, which is a light-hearted series about a girl who wants to be a chef at an Italian restaurant.
My recommendations would be: The First Shop of Coffee Prince, Soulmate, Hana Yori Dango, The Last Scandal of My Life, and the ones I'm watching right now.