Documents: Your passport and boarding documents always go in a carry-on — never in checked luggage.
E-reader (Or Real Books): Yes, you'll actually have time on your vacation to start that novel that's been sitting on your bedside table for months.
Camera: We've given up our big camera in favor of our iPhone, but every once in awhile we have long-lens envy. If you're after that perfect sunset or wildlife shot, come prepared.
Mini Surge Protector: Cabins tend to have few electrical outlets. To avoid having to deal with at least one device always down near 10 percent, bring a power strip.
Large, Sealable Plastic Bags (2): The go-to solution for all sorts of situations, these carry damp bathing suits, protect electronics from rain, and ensure souvenir hot sauce doesn't leak.