I believe that we are in the last days of the "Age of plenty".
We are about to enter the chaos of the "Age of shortage". This will be characterized by the peak of our resources, one by one, in a relentless grind of decline. There will be less of everything. You will not assume that you can buy anything you want.
The most serious of these is, of course, peak oil which is the magic pixie dust of our civilization. Swapping to less agreeable forms of energy will cause big ripples in the pool. Our goods and services are shipped all over the world and country. If shipping costs rise, or becomes impossible, the knock on effects will mount rapidly. If you are thinking of economic hardship, then that's right but it's just the start (and what we are seeing now). When the economy starts recovering it will be smacked down again by high oil prices.
Food is a serious issue. Recently there have been weak but definite signs of problems in this area. Japan ran out of butter (mostly due to protectionist policies), rice producing countries started hoarding (causing riots), wheat has problems (due to droughts) and corn used up in ethanol production.
Most people I know believe that the recent "GFC" (Global Financial Crisis) is simply a downturn which will reverse itself in time, if not already well on the way to doing so. I don't. I believe it is a symptom of the change of this age, and we will see a fairly constant stream of problems with our society from this point onwards. We simply can not resume the growth model we had, it is broken due to the fact that we have hit the edge of the petri dish.
The decline may be frighteningly rapid as it is being delayed and hidden as much as possible. I think that resource conflicts (read:wars) are highly likely, probably with some fictitious ulteria motive. Of course, you can consider the Iraq farce proof positive of this already.
What can you do?