cabinboy – The 17% decrease is for new homes only, which include condo conversions. Up to this month, y-o-y resales have been steady, for both condos and SFRs. When November figures come out, you will probably see the first drops over 2% for condo and SFR resales.
Here's an interesting article with comments from a UCLA economics professor:
"Whether prices go down or stay the way they are, you can pretty much guarantee that whatever the value of your house now, that's going to be the value of your house in 2011."