I think we'll have both at the same time. We already do now but in a much smaller scale than it will be.
We can see deflation in the price of homes, businesses, large vehicles, construction equipment, job losses and many stocks and an increasing number of bonds.
On the inflation side we have gas, electricity, food, clothing, insurance (driven up by disasters), etc.
For the future, I think we (US in particular) are going to have a systemic collapse. Bernanke has admitted that he had to rescue Bear Sterns to prevent systemic collapse. The investment banks and commercial banks are all tied together so the fall of a critical domino bank can take out almost the whole set.
There are so many possibilities that can trigger the collapse, it is quite scary. The following is a more complete list of dominoes I see.
End of the petro-dollar (more oil exporters won't accept the dollar)
Loss of faith in the dollar (those holding mega dollars such as oil exporters and China start trading them for other currencies in a panic)
Loss of faith in the US Treasuries (similar to the dollar above, the US has been spending more than it produces for years, would you loan to someone like that?)
Large bank failure
Large investment bank failure
Even more massive residential foreclosures (they have been accelerating at a high rate)
Many commercial foreclosures
Stock market crash
Bond market crash
Massive credit card defaults
Sharply higher oil prices
Fuel shortages
Electricity black outs
Inability to obtain loans (mortgage, credit card, student loans, business loans)
Large business failures
Even more climate change disasters (floods, hurricanes, fires, drought, etc.)
Collapse of the derivatives (said to be hundreds of trillions of dollars, more than the value of most everything on Earth)
I think many of these will happen all at once, feeding upon one another. You can find data and excellent references for most all of this in
Housing & Financial Collapse Thread
Imagine, the banks collapse, your money in the bank is gone (the FDIC has less than 1.2% of reserves for what it insures), businesses have lost their money in the bank as well. Businesses have no money to pay their employees so employees stop working (deflationary). The Fed and Treasury will start creating massive amounts of money (electronic and physical), because they are broke already, to try to get things going again (inflationary). As the dollar rapidly loses value, oil exporters, China, India, etc. will refuse to accept the dollar and will dump their Treasuries (inflationary). Suddenly, the US imports will be limited to our exports causing an immediate and drastic oil and natural gas shortage. Things we no longer manufacture in the US will skyrocket in price or will be totally unavailable.
I could go on and on linking in all of the other items in my list.
Looking at the above, it appears to be mostly inflationary, but the huge size of the derivatives means their collapse will take a lot of money out of this world.
These pains will be felt all over the world, I just think it will be worse for the US because we are so fossil fuel dependent.