You may not need the toothpaste, floss and mouthwash because it's already in the bathroom...at least it was on the Spirit last Jan.
I also think about the things that I may buy on the ship or at port and don't pack those. I always buy a tee shirt or two,almost always a hat, bucket or baseball cap, usually a beach towel....whatever it is you buy, don't pack its counterpart. Don't forget batteries for portable CD player or whatever.
Finally, pack a great and thankful attitude because you are fortunate to going on an awesome vaction so it should be enjoyed...no bad tudes allowed!
You almost forgot underware? That's too funny.