The NASDAQ bubble went from around 5200 to 1000. That was an 80% decline. If the housing bubble follows the NASDAQ, we will be back to buying homes for 40,000. The big difference in these bubbles is that when most people buy stocks they own them 100%. If the markets drop, you lose a percentage of you money, but you still have some money left.
In the housing bubble you can end up seriously "upside down". This will lead to a wave of forclosures where the debtors have deficiency judgements placed on them. This will leave them pennyless, in heavy debt, and homeless. This bubble is MUCH more dangerous than the stock market bubble. And with the new laws, many will not be able to escape the Banksters rath through the use of bankruptcy.