Do you think it is a good idea to do business with your friend? I always am wary of doing this. If something went wrong, you would lose both your business and friendship.
It seems ideal, because going into business with a stranger doesn't seem right. However, like Jason said, I would avoid it, because you just don't know what will happen between you if things take a turn for the bad.
You might end up finding out that the person who you knew as your friend is totally different when in the role of a business partner. Money tends to change priorities and perspective.
I try to keep myself from making business relationships with my friends. Zimmer is right. Just because someone is great to make friend with doesn't mean he is also great to do business with.