Me, I haven't really gotten into Japanese music that much. I pretty much got the songs from the openings and endings of a whole bunch of anime. From that, the only rock I have listened to are from Asian Kung-Fu Generation, Flow, and Orange Range. Everything else is pop (ex. Gundam Wing, FMA), so it really doesn't count in this topic.
I do plan on getting some more music by those rock bands, particularly AKFG. Heh, that group is so good, although their music videos for Haruka Kanata and Riraito are a little on the boring side (yeah, they just play music the entire time, no excitement). Any possibility that I can d/l any of their CDs from the net, or is that not allowed here to post a link? I would try supernova.org, but I'm at school now and class is about to start.