Of all the shows I've been to, I only brought ear plugs once and I found they detracted from the experience (I couldn't hear the instruments properly, like half of the music was wiped out - they were made of memory foam). I haven't experienced any discomfort during any band's performance (either metal or rock or whatever), and only slight ringing afterwards, and that only happens occasionally. While ringing in the ears is usually a sign of damage, I haven't noticed an overall decrease in my hearing ability. More often than not it shows up in the latter years of life.
As far as suggestions go, I can't think of anything that hasn't been brought up, other than maybe just positioning oneself away from the speakers. I don't know, I think I agree with Plintus on this one. Minus all the parts involving penis. That's just him.