I'd choose gold. AFAIK most all money laundering rules deal with cash.

Even if a geine were to give you 500 tons of cash or gold, some governments may have a problem with that and choose to redistribute it.

Choosing gold makes the value much more liquid in my opinion.

Not to mention that gold doesn't rot (unlike USD). In today's economy gold is probably more value-dense (as in, a pound of gold is worth more than a pound of hundered-dollar bills).

Currencies also come and go but gold stays. If you're thinking long-term, gold is the vastly better choice.