I think "metal" and "drinking" has nothing to do with each other! There is drug-use in almost any kind of music-genre (dunno about classical music in detail, but I listen to it aswell....) and there is drug-use in many kinds of non-music-hobbies, just for example sport-fans..
Personally, I drink very seldom, but to concerts I go (and usually leave) sober, because I don´t want the music-experience being spoiled by not being totally aware of every detail. Though I probably try out one day, what is the difference (maybe for a "less important" band to me), because I would like to find out how the concert is when you are high
When I listen to music at home (I think that was the original question *grins*) I go for coffee or other "normal" drinks.
can´t say I see any sense in drinking anything particular just because listening to something particular.
the occasion is way more crucial than the music.
I've attended to many live performances that require drugs to maintain some coherence all along the show, unless you wanna realize at a conscious level what you paid for.
As for me, I need booze to be sober, which makes it less interesting but amazingly cool when you're a teenager and you have some social duties to attend to.