I voted for Sepultura.
Because they deserved it. I followed them through four albums, and on the last "true" Sepultura album "Roots" their sound reached an all time high. It just sounds like it should, thick, meaty, heavy. A lot of it has to do with how friggin hard they pound their guitars, and the overwhelming attitude with which they attack them. A lot of it also has to do with the fact that they are crazy Brazilians. I remember reading an interview with the Korn guitarists where they claimed that Sepultura stole their sound. I laughed... there is no way that chumpy Korn sound is even close to the all out brutality of "Roots." Check out a song called "Straighthate," that's Sepultura in a nutshell.
The sound on Arise and Chaos AD is not bad either.
I would give a close second to Prong, on the Beg to Differ album. That was a sound that changed my whole approach to heavy guitar.
Metallica Justice is #3 for me. That's an album that is just too heavy to be played on most home stereos, the bass in those multiple guitar overdubs is just too intense. The definition of prog-heavy, that's about as heavy a sound as you can get while still retaining the clarity required for something like "Dyer's Eve."
Slayer in the old days was never really heavy, that was what was so cool about them. They were basically playing death metal with a 70's rock sound.
Kyuss! now that's a monster sound.
