A lot of people ask me "What are the best colors for our photo shoot?"  But in the same breath request me to shoot the Navy and White combo. Navy and white generally don't work well, unless you are in the right light. This is a risk, because you never know what kind of light your going to have til the moment of the session. Navy sometimes appears as Black, and White usually will be to bright (blown out). In a group of people wearing white, white does not translate well photographically  (one/two people might be ok) I usually would recommend something in the Blue family, (powder blue, teal, light blues, etc.) Another option is coral or anything in that family.  As far as combos go. Khaki and a coral or Khaki and blues work and or white supplimentally, again not as a group. In this instance white will work as a second color as well.