Been pondering this vary topic for years, and IMHO what is going to happen depends very much in what part of the world you're in and what social/economic class you occupy.
The over all trend I see is downward because the amount of resources is not up to the overall demand.
Basically while skimming this thread, someone mentioned just look at the third world and with that statment I'd have to agree! The analog models I have for disparity within a society I'd say might be the philippines and cuba. Life in both these cultures IMHO mirror the global population as a whole because if you have the chance to visit either country and get to see the culture up close and personal one would see a vast gulf between those individuals, who are well educated and connected have the opportunity to live pretty good. I'd also say both these cultures are good analogs in that the vast majority of people in both these cultures suffer from a system where governance is highly biased toward those individuals what have educations and connections to begin with.
On this board there are lots of people who are looking at a doom and gloom, mad max lawless future, and I'd don't see that happening to the USA in my lifetime which hopefully is 60 years+. The reason I say this is because the USA has lots of things going for it despire the economic firestorm going on around the world.
On the plus side of the equation, the USA has a strong tradition of rule of law and a very innovative spirit, which allows small invative businesses to grow and produce goods and services which people want, without fear that a corrupt government official is going to try and muscle in and take everthing away. In the rest of the world, the barrier to entry for a small business is very much higher than it is in the USA.
On the down side of economic equation in the USA is the state of entitlement and ever increasing expectations. There also has been a mis-match between the skill sets needed to thrive in a world where there is diminishing resources per capita.
Hate to put in in blunt terms, but the average person anywhere in the world is basically a sheep that follows the herd and does not have deep thoughts or takes major economic initiative. Like a flock of sheep, I see the global population growing over my lifetime, BUT the general health of the flock of sheep in general will be very poor which will make the flock susceptible to sickness and disease. I'd say within my lifetime I fully expect some kind of global pandemic will occur because detoriating infrastructure which is overwhelmed or rather unfunded due to the declining economy.
Looking at the bigger picture but the analog models for past pandemics (such as Bubonic plague, or the 1918 flu out break), will not be sufficent to calculate the raw carnage thats possible in a world that is highly connected, with population densities never before seen.
http://virus.stanford.edu/uda/For example the last major plague in 1918 killed upwards of 50 million people, I see the potental if something similar hit in the near future, that upwards of 750 million people around the world will not survive because of squalor caused by poor global economic conditions.