Jpop / Jrock suggestions?

I know that this has been asked several times. I'm new to the Jpop / Jrock scene. I've got a few Gackt songs, I like what I've heard of L'Arc-en-Ciel, though I don't have any of their stuff. I have a varied music taste, and iTunes (which offers some of this genre, but it's hard if you don't know who to choose). Some of my favorite American artists are Linkin Park, Blue October, OK Go, Michelle Branch, Switchfoot, Mandy Moore, Avril Lavigne, Ana Nalick. It's a varied taste. Any suggestions would be appreciated!