i would choose gazetto...i´m listening them for a very, very long time and i am really not tired of their music...tokyo dome concert just made me cry...
they have a great music...can´t wait for vortex...
but...they are several groups and artist who are doing a great music...everyone has another taste...but from those i liked...i would reccomend...:
the gazette
gackt
miyavi
vivid
born
alice nine
d
120 12
x japan
kuroyume
luna sea
daigo
anna tsuchiya
matenrou opera
if You like some pop...i would reccomend these...:
ayumi hamasaki
kat-tun
koda kumi
namie amuro
anna tsuchiya
hey!say!jump
tomohisa yamashita
jasmine - rap, rnb
from k-pop...:
big bang
2ne1
dbsk/tvxq/tohoshinki
mblaq
top teen
SS501