I dont think music in itself is evil (like the early church monks used to think there where evil intervals like the tritone) but what is done with the music and the various bad messages (kill yourself, worship evil, womanize, etc...) it can contain. For instance before I came to really know Christ I listened to a lot of music that I dont listen to know, for example Nine Inch Nails. Im a huge fan of electronic music and I think Trent Reznor is a real genious. Unfortunately I just cant listen to his music anymore, because of songs like "Heresy" which goes, " God is dead and no one cares, if there is a hell i'll see you there". It brings me down.