depends on the type of metal, I am really into my black metal at the mo for which the moves are either a menacing dour stoic look or hand out holding the invisible heart of your foe, tongue out and manic eyes ala Immortal or similar.
other than the headband like f*ck. though careful when i saw 1349 their bassist got his hair caught in his tunning pegs and ripped a huge chunk out mid set, kept going without flinching thought...now thats true metal.