I can not stress enough the zipper bags and freezer bags. We used them for wet things, shells, medications etc.
Also I bought a 2 pack of little flash lights at Wal-mart and they were handy in finding the bath room or things at night while the little ones slept.
Bottled H20 which I refilled my bottles with the ships H20 on Deck 2, tasted good to me and I am picky and obessive about my water.
The quarters, shout wipes and laundry tablets are a must!
Next time I also am going to take a little thing of dish soap. It was hard cleaning sippy cups and even the soda mugs after a few days.
I travel size (Target travel aisle) pack of antibactetial wipes is also handy.
I also found packing everyones things in see thru cosmetic bags (Target) was a hit. You could easily go to what you needed. Now I have little ones 2 under 4 so the over the door shoe hanger was not needed but my Category 9 had a shelf over each sink and shelves in corner which I put each persons cosmetic bag on and it kept everything neat and tidy and out of the way.
Books and magazines of course if you even have time, plenty of film, and an extra battery for your camera. A under water camera.
Being a melanoma survivor I suggest lots of sun block and lip block.
Sun glasses and a hat. I could go on but won't

...........Have fun