Ok, here's the follow-up I promised:
Heavy Metal= Medieval Weapon + President Name
Battleaxe Jackson; Catapult Pierce
Death Metal= Nickname + Internal Body Part
Snookum Spleen; Scar Mastoid
Alt/Indie Rock= an element + (part of) classic book title
Wind of the Baskervilles; Europium Gables
Country= City + Pet's Name
Rabbit Hash Rover; Tallahassee Yeller
HipHop= famous landmark + garden tool
Macchu Picchu Hoe; Taj Mahal Weeder
Boy Band= mode of transportation + flower name
Bowrider Cornflower; Skateboard Snapdragon