Metallica - Kill Em All

Metallica's debut album--originally released in 1983--is a fine piece of thrash metal, and as good a marker as any for the debut of the genre. Several of the songs from this 1983 album have since become classics, including "Seek & Destroy", "The Four Horsemen", and "Jump in the Fire". The song writing isn't as sophisticated as on Metallica's later releases; still, it's a great listen, and essential for any heavy metal fan.