I've been working on Metallica tones for their first five albums. The goal was to get as accurate as possible. Here's where I ended up! The video quality varies quite a bit but all the guitar playing is recorded direct to the computer via USB with no mixing or any kind of extra processing added. It's straight Helix.
Seek & Destroy for that gnarly, old-school metal Kill 'Em All tone
Fade To Black with Hetfield's revamped and modded Marshall tone