well ill mention some awsome bands for you.
disturbed, in flames, manowar, kamelot, sabaton, U.D.O, bring me the horizon, atreyu, hinder, satyricon, pantera, three days grace, marilyn manson, dragon force, system of a down, sonata arctica, within temptation, entwine, nightwish(not the new poo but the old. before they changed their singer. new singer sucks old singer sings opera. got to hear it), maximum the hormone( only if you like japanese tho. but if you do they are amazing), godsmack, volbeat, five finger death punch, children of bodom and guano apes( not realyl sure if they count as metal but they rule).
that should keep you busy for a while :p