As for Death Metal band, look at my profile and guess -
Behemoth is my second favourite, so it was killer when I got to work the Behemoth/Necronomicon show in Vancouver 2005. I also revere Morbid Angel and Death (the originators), Angelcorpse, and Yyrkoon.
My favourite all-time Metal/Hard Rock band is Witchfynde, with Mercyful Fate and King Diamond as not even really a second, just a different fix. King is God. And...Priest and Sabbath cannot be contended with, and Pentagram is a no-fuckeroo. METAL!!!!