I hate to be the devil's advocate, but, you can't always count on your luggage making it to the ship. On a recent cruise to the Med my wife and I were left luggage-less for days in Barcelona. The experience caused us to reinvent the way we packed and travel for a cruise. We came up with a carry-on packing list that made sense in case you were without your checked luggage.
You can find the list here:
Even though it is entitled "Before You Book" It is rally about how to protect yourself from problems getting to and from the cruise. I hope that helps.