Purse, clothing and ID
For clothes I love TravelSmith - nothing wrinkles and it so wash and wear... super comfortable.
For a purse/bag, I always use a lightweight one I can put over my head and carry across my body. REI makes some very practical, cute ones. Inboard I always carry a wristlet (small purse, about 3" or 4"x6" with a small strap to go over your wrist) with my ship card, room key and gum... What more do you need?!
Yes, keep your passport locked in the cabin safe and carry a photocopy when you go onshore..
Norwegian Sea, Roatan/Belize, Apr 2004
RCCL Splendour of the Seas, Western Caribbean (Cozumel/Costa Maya), May 2007
Princess Diamond, Mexican Riviera (Puerto Vallarta/Mazatlan/Cabo San Lucas), Sep 2006
Carnival Paradise, Catalina Island/Ensenada BC, Jun 2011