Anyone know of any J-pop/J-rock bands?

[Saeko]

Tohoshinki
TVXQ
DBSK

They produce the best music ever !!

B)

[Joshua]

Most of the artists you guys are listing did anime songs... heheh I can't imagine why.

I recommend 嵐 (Arashi) for J-pop. "One Love" and "Crazy Moon" are among my favorite songs.

Then there's this one awesome song 「そばにいるね」 ("Soba ni Iru Ne") by 青山テルマ (Aoyama Teruma) featuring Soulja. You just have to listen to it.