According to the Stock Trader's Almanac, the Dow Industrials peaked at 381.17on September 9, 1929. It bottomed on July 8, 1932 at 41.22--about a 90% hit. Unemployment during the depression was, I believe, around 25%. That was at a time when more people had manufacturing jobs. Now we have a lot of service jobs. Demand for a lot of services will not wane as much as the need to manufacture big heavy things made of metal.
My first thought is people who are over leveraged will be the most affected as we are seeing in the housing markets. The housing boom that was in effect 1998 -2006 saw house appreciate to a level that was not justified followed by the ease in credit restrictions that allowed everyone a piece of the American dream. Mortgage brokers (I know a few) were offered incentives to push ARM's with the promise that you can refinance later and lock in a low rate.... Here come the problem, rates rose, housing gluts reduced prices and "stupid" mortgage companies adjusted rated to levels that the consumer couldn't afford - hence the foreclosures.... In hind-sight the better option for the mortgage companies would have been to lock in the current rates that could be afforded and tighten the credit limiting new loans..... (Feel like I am preaching)......
Anyway, will we have a depression like 1929, probably not the global economy will balance out as the reducing dollar makes goods and travel to the USA a bargain. Will we see tough times, yes but I believe we will hedge to a better economy in 2009, post election (regardless of the winner)..... We will see people unable to get home loans without a 680 fico and 20 to 25 percent down. The days of no down payments and low down payments will be limited to the 780 fico scores....... The stock market will correct but probably in the 25 to 30 precent range.....
The biggest problem is the biggest asset most people have (their house), will reduce in value regardless of locations, 401K's will also reduce...... Instead of the 2nd house at the beach it will be the fifth wheel at the state park for vacations.