Since everyone is quoting the California Association of Realtors percentage (loss/gain) comparison from Feb'07 to Feb'08, I'm linking it. You can view the city-by-city comparison in each county. Many of the percentage changes are not near 26%; some are over; and some are still on the rise.
Feb 2008 Median Home Prices
California is a huge state, with an economy that could be compared to a small nation. The weather is a positive that draws many people away from snowy/colder areas. The wages help a lot in what we can afford or not.
The housing situation here is a compilation of effects over the last 5 years ; some areas are more affected than others. Yes, this is a market correction long overdue. Yes, many many houses are still overpriced.