Los Altos Hills is a great location. It is a small community with a very limited ability to build new houses. The supply/demand ratio will continue to be short supply verses demand. That will maintain prices.
There are certain areas in the Bay Area that haven't really been affected by the housing crisis; Los Altos Hills is one of these places. I wouldn't expect the property prices to fall at all, not to mention the inventory in this area is so low ... there are a lot of 'heirloom' homes that never hit the market because they are given down and entrusted to family members. How about Los Altos, Mountain View or Palo Alto? Again, these areas are still not affordable to the typical home buyer, but they are less expensive and close to the hills.