Up. The only downward pressure that area will experience wi come from sellers that have to sell and fewer buyers that can qualify for loans.
At the prices and desirability of Cow Hollow that is a very small segment of the market so not much pressure.
Any seller that can has to move and can rent the property until the credit market is stabilized will hold till then. Rents are going up in most areas of SF and the north side is always a strong rental area.