KILL 'EM ALL

For better or for worse, thrash metal started here. Personally, I would say for better, as I've always been a fan of the genre whenever it's been done right. This is actually one of my favorite thrash albums, but saying it's Metallica's best is ridiculous. The lyrics are undeveloped, the percussion is lame, and the songs get repetitive at times. But the riffs...that's where this album sticks out. The guitar riffs here are great. Each song has plenty of them complete with excellent accompanying solos and tricks.

If you want to become a thrash fan, everything that's good about it is pretty much here. So, yes, I'd recommend it, but calling it essential would be insane.