Iron Maiden - Piece Of Mind, the first ever Maiden album I ever listened to. I can safely say these guys have taken more metalhead music virginity than any other band in the world, as for their cover art, nothing says Heavy Metal more than Eddie the 'ead.
IRON MAIDEN albums, not including live ones. Still the best IMHO is the first one! The worst are 1995 and 1998 when Blaze Bayley took over from Bruce, though I'm not blaming Blaze; they just weren't very good. Bruce returned for millennial offering Brave New World which is a great album. Long live the Irons.