I am a complete novice when it comes to metal, but here goes:
Metallica: I really only started to pay attention to them when I saw the videos from their self-titled album, so I got that one. But I also got Reload, mainly for the song The Memory Remains. It's a great song, especially with Marianne Faithful's backup voice. While it's clearly a tribute to the demented former actress Norma Desmond in Sunset Bvd., I can't help but think of the Fayth of Anima when I listen to it.
Tool: Another good choice. Especially Undertow.
And I know this isn't metal per se, but I think Information Society might be right up your alley, Nominus. Not the well known album with the Star Trek samples, but a later album filled with dark techno music, Don't Be Afraid. Especially the demented brilliance of Ozar Midrashim, which will be instantly recognizable to anyone who has played Soul Reaver. I'd be very surprised if you didn't like it.
BTW, Don't Be Afriad is out of print, but a lot of the tracks are on a 'very best of' album for IS.