Best Metallica album ??

I had to go with Master of Puppets because that was the first album I was introduced to. Saw them open for Ozzy during that tour, Cliff Burton was still making magic with the bass. They blew Ozzy away (he was totally blitzed and barely sang anything). I think Burton died about 3 months later. Saw them a few more times after that as well, but that show really sticks in my mind 30 years later!