During a team Halloween event one year at work, we were all asked to tell one thing that scared us. One of my very stylish co-workers said, "Navy blue and black together!" I always think of her when I pair the two colors.
I think that, as long as it's very apparent that the combo is being done purpose, there's something chic about the whole thing. If you ever see me walking around with one navy shoe and one black shoe, I'll of course try to convince that it was a purposeful style choice. Of course.