I agree with Daniel that the price decreases in the next 5 years will be much, much closer to 0% than to 50%.
Right now, I could spend a couple of hours of research time and present you with 50 specific properties that have dropped by quite a bit over the past 12 months, (10%+), but I could also present you with 50 properties that have not gone down at all over the past 12 months, and another 50 properties that have had sizable (over 15%) price increases over the past 24 months.
The bottom line is: for most areas, (downtown condos and some newer tracts excluded), prices have changed very little, up or down, in the past year. And we really don’t know how much prices will drop over the next 4-5 years. There are too many factors involved. The only things I know for sure is that there is a lot of inventory right now, which will keep some downward pressure on prices in the next year. And also, there is very little sales activity right now, which will keep inventories high. Most potential buyers seem to be sitting on the sidelines until they see what happens in the housing market.