Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report; if there be any virtue, and if there be any praise, think on these things.
In this single verse is summed up the proper attitude and mindset of a Christian.
Thats why I really like this verse. I've read it before and my Bible says to use this as a screening for any action you might do or any music you'll listen to.
In a way this verse dovetails into a quip I once made to a friend: "If you don't want the Lord to know it, don't even think it!