lol, wow. I haven't listened to J-Rock in a while. I prefer the darker, heavier stuff like Dir en grey, D'espairsRay, Gazette, etc. Japanese Metal is awesome though. Bands like Sex Machineguns, Sigh, Blood Stain Child, and Galneryus are just as good as their American/European counterparts.
Sex Machineguns:
http://www.youtube.com/watch?v=pV8JR2vepD8http://www.youtube.com/watch?v=wMusFPynZJ0http://www.youtube.com/watch?v=LSepbZrXAg4 LOL, their new guitarist looks like a Japanese version of Yngwie Malmsteen.
http://www.youtube.com/watch?v=xLRmzDNxdrA Glad to see they still got it despite the member changes.

One of the best Speed Metal bands I've ever heard.

Sigh:
http://www.youtube.com/watch?v=tBhQY-Kgwfshttp://www.youtube.com/watch?v=nsjQ3Suof3kQuality Black Metal from Japan

Blood Stain Child:
http://www.youtube.com/watch?v=b7EkveEZbmQ This songs sounds like Children of Bodom's stuff, with some techno influences.
http://www.youtube.com/watch?v=2oi-8xl7uZs This song sounds a lot like In Flames newer stuff....with techno influences. The vocalist even looks like the vocalist from In Flames.
Overall a pretty good Melodic Death Metal band.

Galneryus:
http://www.youtube.com/watch?v=zjnNOkjnLVIhttp://www.youtube.com/watch?v=rfBI_kmDlNQPretty good Power Metal from Japan.