I try to get to shows maybe once every month or two. A lot of good stuff comes through Melbourne but I've been a bit strapped for time since I started at the tattoo studio (I have to work a 2nd job at night as I don't get paid much as an apprentice).
Bands I've seen in the last few years: Nasum, Psycroptic, Departe, Lo! (both amazing Aussie bands), Disentomb, Black Breath, I Exist, Converge, Mammoth Grinder, Cattle Decapitation, Dyscarnate, Satyricon, Amon Amarth, The Black Dahlia Murder, GWAR, Deafheaven, Animals As Leaders, Refused, Fear Factory, Dillinger, Devin Townsend, Meshuggah, Old Man Gloom, Katatonia, Deftones, Whoretopsy.
Australia doesn't have many good metal festivals. Soundwave was ok but it went under a couple years ago and now it's just one off shows here and there. That being said, Melbourne has always got something good to offer.