So you have a radio station, but you're not sure what kinda music you play?
But if you're more into clean vocals and melodies rather than blastbeats and scream, you should stick to heavy metal. Try Iron Maiden, Motörhead, Rainbow, Black Sabbath, Angel Witch, Armored Saint, Early Man, Judas Priest, Manowar and such.
This might be a good site to explore things and see and hear what's what in the metal genres.
Map of Metal