Metallica
It's in the name, and the band that got me into listening to music, from when I first misheard Seek and Destroy as 'She can destroy' from their debut album Kill 'Em All in my friend's dad's car.
Metallica are one of (and the most commercially successful) the 'big four' thrash metal bands from the 1980s which also included Anthrax, Megadeth (fronted by Dave Mustaine, the original lead guitarist that was fired from Metallica) and Slayer (who's album cover for Diabolus in Musica used to terrify me as a child).
Metallica's musical career has seen them switch gears to radio friendly hard rock after their first four thrash albums with the seminal and eponymous 'Black Album', to more southern styled rock in the mid 90s, to releasing utter garbage with their big return on St Anger, to trying to go back to their thrash roots in the latter years.
What you can't accuse them of though, is not trying new things. And the last album, Hardwired to Self Destruct was a solid effort which almost feels like Metallica once again defining their own genre of metal.
Fear Factory
So tight and rhythmic is the drumming in industrial metal legends Fear Factory's unbeatable classic sophomore album Demanufacture, that I often put it on to help me fall asleep. No, that doesn't mean it's boring, it means it's so well put together that you can let your consciousness drift away, safe in the knowledge that you won't be jolted by any misplaced jarring sounds even on tracks with titles like Body Hammer or Hunter Killer.
Burton C. Bell's mix of clean and unclean vocals predates the more famous efforts of Slipknot, and are actually more melodic.
Tool
Or TOOL as they seem to write their name now, are a bunch of virtuosos that are such perfectionists, they've released just six albums in 30 years.
Are they hippy trippy prog metal, are they just alternative metal? They're both, and who cares, what matters is that you put on the song Ænema from the album Ænima and hope to flush it all away.
