Swedish Viking-metal powerhouse Amon Amarth were already a big band when they dropped their seventh album, Twilight of the Thunder God, in 2008, but the LP made them a bona fide juggernaut. Hitting No. 50 on the Billboard 200, the record stands as one of the groups catchiest and crushing-est offerings, stacked with vicious riffage and Johan Heggs fjord-rattling war cry. Adding to the epicness are guest turns by Entombeds L-G Petrov, Children of Bodoms Roope Latvala and headbanging cellists Apocalyptica.