The stuff that they discuss in the metal thread - no. I have tried to listen to some of it but it is not for me. Maybe something will turn up in this topic, we will see although it is generally not my style. I am into more laid back music these days.
http://www.youtube.com/watch?v=3DUQa9sQX4g&feature=related (or at least by my standard).
A lot of Electric Wizard songs are horizontal.
But, otherwise, the rules in the metal thread are there for a reason, they are quite easy to understand I think, they still encompass a massive amount of music, from bands like Agalloch to those like Bathory, the rules are there to make life easy, there is after all a massive amount of variety in the metal genre, tagging other non-metal genres of music (however similar) just adds more effort into finding music people enjoy.
Somebody was talking about "noise" music earlier, I'm not really knowledgeable on the genre myself, but you should definitely check out Sunn O))) as well as Xela's "In bocca al Lopa", phenomenal noise work. There is of course a lot more, but they are the only two off the top of my head that I listen to.
I'm also a massive TOOL fan, I still think "Sober" and "Wings of Marie" are my favourite tracks.