Yeah I do this too....
Bleeding Through - dark/staff tank
Allegaeon - Psi/energy scrapper
Opeth - Ice/Water defender
Infernal Deicide (band name is just Deicide...I typically use "Infernal" in my fire toons) - fire/kin controller
Silent Lucidity - ill/rad controller (Not a band and not necessarily a metal song, but............)
Infernal Dominion - fire/dark corrupter (Dominion a great death/doom metal band)
Sinsaenum - dark/dark defender
Infernal Nergal - spines/fire brute (named after the lead singer of the great death/dark metal band Behemoth)
Fozzy - savage/wp scrap
And ideas for many more!