In my opinion it is Global and the efforts you put forth should be a wide spectrum of metal collection. Remember, buying nickels and pennies is not a negative investment in any way, it will only benefit you in the future and a bank will take a house payment in pennies and nickels if need be, with no loss in face value. Silver and Gold should be seen as progressive store increases as you can afford them and when the price is down. Never sell unless there is a spike that truly benefits you. Otherwise, hold on to all metals as they will always go up in value. Currently silver is a great deal and smart to buy as much as you can. Gold, may still be overpriced at this point but it breaking $1600 brings some hope to it's future. Gold, in this scenario, is the longest investment and it ties up a lot of paper for a small amount of metal. I did not start buying gold until I had a healthy stash of silver, nickel, copper and zinc.
The global nature of this is mainly set in the nickel, zinc and copper. The reason why the US government is buying back these metals and phasing out these coins content with clad is because the metals in them are the very metals of our future, metals that create batteries and in every sense, the world is moving in this direction. Once pennies and nickels have been phased out you will see a rise in price 10x face and beyond. Look at these metals in the same way smart people saw silver in 1965! Grab it with both hands and store it like a squirrel!