It's impossible to say that God is against music for He created the ability for man to produce and enjoy it. Consider verses like Psalm 81:1-2, which call for us to "sing aloud to God our strength; make a joyful shout to the God of Jacob. Raise a song and strike the timbrel, the pleasant harp with the lute." Yet, there is a right and a wrong type of music evidenced by the fruits or results it produces.
The key in determining what music is acceptable before God is to examine the message and even the mood each song produces. Sometimes the message is obvious, while at other times it is subtly embedded in the song. Sometimes a song even contains multiple messages or produces depressing or rebellious moods. Regardless, when we come across a song with a message or a mood that clashes with God's way, we should try to avoid listening to it.
This can be difficult. Often we can justify continuing to listen. Maybe we're "not paying attention to the words" or mood, or maybe whatever's wrong with the song "isn't that bad." But we must keep in mind that the ultimate source of evil in this world, and of the wrong messages in those songs, is none other than "the prince of the power of the air" (Ephesians 2:2), Satan himself. The Bible warns against giving the devil a foothold (Ephesians 4:27, New International Version)—and by willingly allowing music that promotes his way into our lives, we do just that. Satan throws enough garbage at us without our help; do we really want to be giving him a hand in attacking us?
Another test for any song is simply this: Would you be comfortable listening to it if Jesus Christ were in the room with you? If your answer is no, it's time to rethink why you're listening to it—and whether or not it's worth your time.