Rock
Metal
Techno
J-Pop/Rock
As far as what japanese it is, (since everyone seems to be listing)
KOTOKO, I've, Janne Da Arc, Larc en Ciel, Siam Shade, Asian Kung Fu Gen, The Pillows, MAXIMUM THE HORMONE, High and Mighty Color, fripside, (some) B'z, Acid, The Calling, MintJam, Mami Kawada, teranoid, (some) Terra, Bump of Chicken, Abingdon Boy's School, Nightmare, DJ Sharpnel, Tommy Heavenly 6, UVERworld, T.M. Revolution, M-Flo, and then there are like a bunch of random songs i've picked up over time. <_<.