There are many japanese musicians i love. They are mainly known for their anime songs.
UVERworld (combining rock and hiphop, probably many people know them)
NICO touches the walls (they have very good songs)
Radwimps (not Anime-related but a very nice and interesting band)
Has anyone heard of these bands before? :)
Ryuudo, I love all the ones you mentioned :O!!
Radwimps got anime related since Kimi no Na Wa :3