Short term versus long term
Short term - food, water, guns, ammo, items for barter, etc. Lots of good discussion on short term survival on this list.
But if your short term preparations work the way they should, then what? Now you are into long term survival. The short term is just that - short term.
The Great depression lasted more than a decade. It is not practical to store 10 years worth of food. Most food will start to deteriorate long before that and the sheer volume is daunting. The short term panic will be over shortly after it starts. The criminals will kill each other, or be killed by armed folks protecting their communities, or will starve. The weak will die off. Those who are left will form simple, local economies. At that point your short-term preparations run out of steam. It is true that you can't eat gold in the short term. But there has virtually never been a time anywhere in the civilized world that you couldn't use gold to buy something to eat. That might not be the case in the initial panic, but it WILL be the case before the hard times are over. A LONG time before the hard times are over.
The simple local economy that we will have to survive in will last for many years. It will run on barter at first but will move quickly to some kind of currency because barter is inefficient. This will almost certainly include silver coins. It may include gold. It may include silver and gold minted in foreign countries. Down here in the Southwest, I think it is very likely that Mexico will issue silver coins and they will circulate. To the extent you have silver and gold you can buy what you need. But in the same way that you cannot store a decade's worth of food, you are also not likely to be able to store enough gold and silver to live off of for a decade or two. So what are you going to do?
You need to find a way to participate in the localized, simplified, subsistence economy that is our future. What skill can you offer your fellow man that they will be willing to pay you for? What tools do you have that will allow you to render valuable service? What knowlege? What relationships have you developed with other patriots that will help you build a community?
Prepare for the short term. But prepare for the long term as well. I believe that includes precious metals. But it also includes a plan for fitting into a local economy.