Hmm, good power metal band is Holy mother. Hard to find, but their newest album, Criminal Afterlife rulez...
Good deatmetal band is Soliwork (but IMO Natural born Chaos (or something like that) isn't good... I more like The Chaiheart machine)
Good death metal band is also Fear Factory, check out their best album - Demanufacture. Vader is also good.
And black metal - Borknagar!!!!!!
Megadeth: rust in peace
Iron maiden: pice of mind
Rammetein: herzelid
Six feet under: grave yard classics
Dimmu Borgir: storm blast and puritanical euphoric misanthropia
Ministry: som 69