I think a lot of the posts in this thread are completely absurd.
When recording metal tones, most people actually cut the bass, and let the bass guitar handle the bass frequencies, and don't scoop their mids.
Yes- you see guys scoop their mids, but they scoop their mids on metal amps, which in most cases have a lot of mids (5150, for example, which is used in countless metal guitar recordings). So really, they are not scooping their mids.
I will tell you right now. That low end you hear that comes from the guitar is not the guitar. It is the bass. The bass is the key in getting a big sound and really the low end that metal is known for.
My advice is to dial in the guitar tone once you have the bass guitar mixed.
These two videos, are pretty spot on for recording metal bass and guitar:
YouTube - Tutorial: Recording metal guitars at home - The Fearedse way... YouTube - Tutorial: Recording metal Bass guitar at home - The Fearedse way