A few people I know compare bitcoin and gold regarding currencies with integrity; Martin Armstrong on Zero Hedge compared both in a recent post. One advantage I currently see that bitcoin has over gold is the cost to verify is much lower; it costs more to make sure that I've received legitimate gold than it does to verify that I've received a legitimate bitcoin. But this depends on the cryptography always being legitimate - what if in the future someone cracks it?
What would happen if someone in the future is able to crack bitcoin's cryptography? Does the system adapt at this point (and can it?)?