My favorites:
Korean: JYJ, S.E.S (no longer together), DBSK, Younha, Rain, Edward Chun and Lee Sun-hee.
Japanese: Rurutia, Hikaru Utada, Kumi Koda, and Sayuri Sugawara.
Taiwanese: Aaron Yan
I also like Silent Sanctuary and Imago, two groups from The Philippines.
The Vanness and Kangta...