Just saw this thread - on the topic of carrying cash in luggage - are traveler's checks still around? I know there's a small fee associated with getting them, but AMEX or whoever you buy them from will replace them for free if they are lost or stolen. Honestly, I haven't used them in 20 years (shows you how often I vacation!), so I don't know whether they've come and gone, but that might be a nice option if you're concerned about your luggage getting stolen or caught in a fire.
This thread makes me think of my mom's advice, which was to carry $100 with you at all times for emergencies. I never, never carry that much with me (the most I have is $20 "mugger money" if I'm in the city), but there is probably wisdom in it in case of an emergency when a debit card wouldn't suffice.