*thinks deeeeep into the abyss of her brain*
best ? IN MY OPINION......O_o I dunno if you would like.....
jpop artist ~ Ayumi Hamasaki
jrock artist ~ Dir En Grey
american rap ~ Hmmmmm..... I don't listen to crap... but could you count Outkast ?
american country ~ Ewww.... country's horrid.....
american pop ~ ..... now or earlier ? I don't really listen to "popular" music ~
american rock ~ Tie between Jimi Hendrix and the Band of Gypsies and David Bowie