Having thought about the question for a while, I would have to say no. It depends on where the two people are in their lives and what their relationship is. But if you're best friends, sooner or later one of the two is going to develop those feelings. Being best friends probably means that your friend already has a lot of the qualities you seek in a partner.
That doesn't mean the friendship is doomed, there is more than one way of dealing with the issue. But as Graham said, if you get together and then go back to being friends, that could well be too hard to handle however.