San Diego may not crash as bad as Detroit, but it may be hitted harder than LA or OC:
1. Geographical speaking, SD’s location is not as good as LA or OC. OC is the center of both and SD is very far from LA.
2. LA & OC have more industries and job opportunities.
3. SD has much more empty lands to build houses by comparing with LA or OC.
I think these are the main reasons that SD house price has already declined one year ahead of OC while LA still increases.
However, the mortgage industry may hurt OC a little! Furthermore, SD mainly counts on defense and tourism. If the economy slows down because of the housing market, the tourism will be hitted very hard.