System of a Down set themselves apart from the nü-metal pack by embracing alternative influences, including punk and Zappa-esque art rock. Abrupt changes in tempo and dynamics are matched by the mercurial vocals of Serj Tankian, who morphs from fire-breathing screamer to impassioned missionary to Arabic folksinger, often within the span of a few seconds. “Chop Suey!” became an MTV sensation and remains one of modern music’s most compelling anthems.