I like to use a fanny pack when seeing the islands, hold just what I need for the day, only take enough cash for the day, leave the rest in the safe in cabin. Its also nice to have your hands free for taking pics.
I carry a purse "backpack" it holds a lot more than a fanny pack, and also keeps your hands free. I used it on board and on shore. This was the first cruise I used something like this and will never cruise with a traditional purse again.
For daytime, a fanny pak works great either on shore or on deck. Also, a Water Safe, is a great souvenir to just carry around your sign & sail card, a credit card and a few $$. Evenings I usually carry a small envelope/evening bag. I wear glasses and must carry an inhaler, tissues, lipstick plus the card, deck plan and events of the evening page from the newsletter. I have a basic small black cloth hobo style bag that really works out well. I never travel with a regular large handbag, but use a cosmetic case in a Tote Bag.
I use a fanny pack, but carry as a shoulder bag most of the time. If I need hands free to take pics or something I can always put it on. We make it a point never to carry large amounts of cash or anything that cannot be replaced. Almost anything I am going to purchase on shore I use a CC. For evenings, I seldon carry a purse. I usually have the camera case and that will hold most anything I am going to need.
I use Tweety's camera bag method around the ship. I almost always have my small camera bag with me that has enough room to squeeze my ship card, the daily things happening sheet folded about 10 times, and a cosmetic or two.
On shore, a small wallet around the neck like Mike for a CC, ship card, and bit of cash.
I usually take a cinch backpack bag - GAP sells them for daytime excursions and on the ship to hold camera/film/gum/room key/drink card/ etc Hands free and lightweight. For nights, I use a purse I can put across my shoulders for more hands free fun. During the beach day excursions, a beach bag works great.
I also have a watersafe, but I was given mine as souvenir from my last family reunion. Which I thought was a good idea, since the reunion was held at a beach. But I have seen them at Wal-Mart and K-Mart. Good luck finding one.