Let me give you a different opinion. I started playing in the school band and singing in the church kid’s choir at age 9 and so have listened to and performd music of the world and Christian songs side by side all my life. I love all music so long as it’s melodious and speaks positive of life (even the 60’s protest songs were asking for positive change). I see nothing wrong with that. I believe that the talent for music is a God given talent and whether you’re using it to make music specifical of/to God, or talk of love (any form) or the beauties of this world, you are giving glory to God by using his gift and sharing it with others.
As to listening to “Christian” music solely, what do you do about the “earthly” songs of Michael W. Smith, Amy Grant or Phil Keaggy (among others), not listen to them? I think you would be drawing a fine line.
My advice, listen to the music you enjoy, regardless of secular or sacred.