I think if you really categorize precious metals as money, then I think only silver is a real "precious metal" money.
Gold still suffers from lack of divisibility which is a core property of money. Prices are generally relatively too low for gold, so this makes trade very difficult with standardized gold coins or gold cubes.
So for everyday goods standardized silver coins, cubes or rounds are a better physical "money".
Gresham's Law
I`m not saying gold=silver, because it clearly is not equal.
But at current silver/gold rates, you can see that from a healthy 20:1 ratio the ratio now is over 60.
So just from an investment standpoint, if the precious markets kickoff, you could make a bigger ROI with silver, than with gold.
I agree with RealBitcoin,
silver has been the money most widely used throughout history among the 2 precious metals, and about the ROI, that is something that I agree as well, one of the reasons for that is that most uses of gold actually preserve gold (examples, jewelry, coinage, etc) while a significant amount of the industrial uses of silver, destroy it. (or make it very difficult to recover)
money. The bad money drives out the good money from circulation. That's why silver had been more widely used than gold through history. People spent silver but saved gold specie...