Dow Jones History
Here is a list of the components of the DJIA throughout time. If you page down to October 1, 1928, and review the list, it looks as though a lot of these companies survived the 90% stock devaluation of '29 to '32 and hung around for awhile longer. A lot are still around in some form. Ironically, a lot of these companies that survived the first great depression did not make it through the 1970-1980 US peak oil event without being bought out by somebody.
Also, this is not to say that they continued to pay dividends throughout that time either.
Also, note that if you had invested in the Dow 30 in September 1928 you would not have regained your capital until 1955 or so, even though the companies survived and functioned, you did not do very well as an investment.
On the other hand, people lost a lot of money by keeping it in cash form in their local bank when it was shut down, so cash is not necessarily a good thing either. A popular alternative was burying it in your backyard. This did not help the Weimar Germans, but was an effective strategy during deflationary times to avoid the perils of banking in an unstable economy.
Other financial instruments, such as bonds, and even government bonds, are subject to default and/or other shenanigans, so are really no better.
If you held gold, you were not necessarily safe either. In 1932, FDR confiscated the nation's gold, forcing people to sell it for $20 per ounce.
Executive Order 6102
I do not suppose that there is any compelling reason why Silver could not also be confiscated by the government at a given point, but holding a lot of silver might be slightly better.
The problem with holding gold or silver, either one (provided you are allowed to), is that you have to do two selling jobs every time you make a transaction: You have to convince somebody that what you have is the real thing, and you will have to negotiate an exchange rate.
Land is only as good as your ability to defend it, or alternately, pay taxes on it. When all of the state and county governments get hard up for money when TSHTF, they will continue to collect taxes. If you cannot pay yours, they will throw you off and auction off the land.
Antiques? Artwork? I think not. It will screw up your mobility, because it will force you to have a house to keep them in, and with a house you have taxes, covenants, and various other ways that a malevolent government can get it from you.
So it's a problem, trying to preserve a pretty big amount of capital in a way that is likely to survive a serious economic crisis.
For smaller amounts of money, there are some options:
Firearms--There is some merit to this idea, except that in a world where all of the gold is confiscated, who is to say that the firearms will not be confiscated also. The "prying it from my cold dead hands" theory, popularized by Charlton Heston, may not survive some future terrorist attack or uprising. I keep thinking that bullets might be good for transactions. A supply of 9X19mm luger rounds may make you a lot of friends.
Drugs: If you really want to make friends, and influence people, an alternative is to buy up and store somehow a quantity of drugs. (note: I am only proposing this as a hypothetical and am not encouraging you to do anything illegal, per the PO.com code of conduct). Unfortunately, cocaine is not a good choice, because it is hydrophilic, and has limited long-term stability.
Cocaine Monograph Other drugs in pill form are reportedly much more stable, and will last for several years. Gotta either cut the police in on the deal or lay real low, though.
Anyway at this point we are stretching the limit of what someone with a lot of money right now could plausibly do with it to preserve it in case TSHTF.
I would suggest two other things (too bad Phebagirl is not around to make this suggestion): Take some of your money, and use it to make friends. Throw parties, give some away to neighbors that need help, and get ahead on favors. If you have a lot of friends after TSHTF you will be better off. The gift that keeps on giving is to move to a small town out in the middle of nowhere, make friends, and use some of your money to run for Mayor. At that point, you will be the government, and you will be able to have a lot more, shall we say, flexibility on enforcement of some of these government edicts.
Also, invest in knowledge: No one can confiscate it. Knowledge about how to make moonshine, for example, might be really useful after TSHTF as well.
Also, make sure you spend enough on yourself before TSHTF from a health maintenance standpoint to make it through a few years of lean times. Keep up to date with your dental work, for example. Nothing worse than having a toothache while the cops are chasing you down while you are carrying around all of your gold. Get in shape if you are not already. Get that kidney transplant or heart bypass you have been needing.
If things get too far out of hand, such as rounding up large portions of the population and herding them into boxcars and transporting them to detention camps, no amount of capital preservation will do you any good.
Anyway count your blessings. If you have money to preserve, there are worse problems to have. You are already ahead of the 90% of the people who are upside down on their mortgages.