Most people would identify "Ace of Spades" as Motörhead's classic LP and they're not wrong.  In fact, the band released six classics in a row starting with their self-titled 1977 debut but it's really "Overkill" that honed the sound that would unite Metalheads and Punks and influence thousands of bands from every possible subgenre.  From Discharge to Metallica, extreme music would simply not sound the same without Lemmy, "Fast" Eddie Clarke and "Filthy" Phil (The Animal) Taylor and there's no more sonic proof than their sophomore LP. 

RIP Phil Taylor