I have both Japanese and western artists on my mp3 player.

Japanese
Ayumi Hamasaki
Koda Kumi
Gackt
alice nine
Gazette
BLOOD
D
Malice Mizer
Moi Dix Mois
Miyavi
Due le Quartz
PIERROT
Tokyo Jihen
Shiina Ringo
YUI

Western
CKY
HIM
System of a Down
Bad Religion
Cradle of Filth
Dropkick Murphys
Goldfinger
The Darkness