My top 5
1) over the door shoe hangar. I used it for all the little things like chapstick, pager, sunscreen, sunglasses, lanyards, medicines, etc. It was the first place my family looked for something.
2) SUNSCREEN, including the spray kind if you plan to have any of the females getting hair braids. It's great to just spray that exposed scalp instead of rubbing sunscreen in and getting your hair nasty.
3) Hats for those shore times with the sun beating down on you
4) Chewing gum (you can't buy it on the boat)
5) OTC medicine like tylenol, dramamine, etc. If you think you might need it, take it. You can't run out to Wal Mart on board the ship!