With all the billions of fresh created money (created out of thin air) being pumped into the US economy at the moment, the real devaluation of the dollar will pick up speed.
The reason why gold and silver are "valuable" and the dollar is not, lies in the fact that gold and silver can not be created "out of thin air". This was exactly the reason why, in better days, currency was backed by gold or silver, thus transferring the intrinsic value of precious metals onto the currency.
The US government has "outsourced" control of the money supply to a cartel of private banks who have, as far as I know, no restrictions on the amount of money that they're allowed to create.
In the end there is more debt than there is money. So there is a lot of people who are constantly looking for money and they can't all get it at the same time. The actual amount of money is less important than the amount of debt out there. If Debt > money then there is demand.
PS: It's far less harmful for society to mess with the value of pretend money, than to take a useful thing like gold, and prevent people from using it for useful things. And because people don't have gold debt it's value is far more flexible. I don't think gold is worth much, and I don't own any, but I don't want to get into gold trading because guessing when the bubble pops is risk I don't need.
EDIT
I reverse my position. Sure, banks have the prerogative create money, but their ability to do so is based on people using the banks. Once banks no longer provide value for people, they lose their money creation ability. So, even banks are limited in their printing of money.
If I were starving on an island, I'd much rather have a sandwich than a bar of gold. Gold is worthless without someone else around who wants it, just like fiat money.
Source: http://news.ycombinator.com/item?id=410830
1. It is needed for industrial/electronics purposes.
2. It is internationally recognized as being valuable, regardless of culture. That is, cultures as diverse as India, China, England, Russia, pan-Arabic (i.e. non-Jews in the Middle East) have all viewed gold as having value, and that over at least 1000 years of recorded history each.
3. It does not corrode or rot the way paper money does. In Israel they recently found some Byzantine-era gold coins, aside from the obvious numismatic/collector value they still retain value for the gold itself.
4. Gold does not require a government to enforce its value. It's value is innate or intrinsic to the thing itself. As such if a government falls or decides to modify the value of a paper dollar (as Mexico, Argentina etc. have done in the past) then the value changes. Gold that you have in your pocket cannot have its value modified by a government order.
Item 3 is simply a property of gold (which you may or may not find advantageous). For instance, the same thing can be said about granite. It does not rot like paper, but that has nothing to do with it's value as a currency.
Item 4 is simply an extension of item 2. The reason a single government cannot control the value of gold is because all the other government's of the world don't go along with it. This is great if your government is somewhat careless with it's money supply, but doesn't have anything to do with 'intrinsic value'.
Regarding 1, using gold as a currency drives up the costs of using it for industrial/electronics purposes, just like using granite as a currency would drive up the price of countertops. But the fact that gold has a practical use does impart it with some value.
However, the value of gold as a currency is entirely due to Item 2. Gold is worth something because everyone agrees it is worth something. It would be interesting to see how this came about. I'm willing to bet gold's value originated in it's scarcity (and the exclusivity of showing it off), but obviously it has nothing to do with anything 'intrinsic' to gold. It's just as likely that an accident of history would have revealed some other rare metal that royalty desired to show off, which would have imparted 'value' on this metal instead of gold.
The reason gold holds value today is entirely historical. People value it precisely because people have always valued it.