The Lord leads. As I've said, I've had a 'best friend' since I was 5 and it's a situation that constantly allows God around them, because I often say to them, 'The Lord leads,' and that my life is after Him. My friends I want in heaven, and, God knows that, I don't think we are to leave friends unless God takes them away, especially when God's used them to help you in life in a lot of different ways, like my 1.5 year older best friend has done in my life, not to mention, his kids and wife are in my life too and have been for many years now.
But, yes, we are to follow the Lord and IF your best friends are taking you off of God's path for your life, having you compromise your values then that is not good. My best friends are good to me, they are a model family of love that I pray daily can see His Love in their lives .