@sciencegirl: Sales and other taxes in Cali are a lot higher than in most areas. Also, living in Palo Alto will require you to own a car (whereas living in Berkeley will not)... and a bike if you're trying to save money on non-rainy days. Gas prices in Cali are ~3.80$ per gallon right now and will surely increase by summer. They have been at 4$ most of the year.
My SO did not get grad housing at Stanford and now pays ~1000$ for a room in a house with a huge utility bill, because most housing isn't built for cold weather... He has to drive to the grocery store... and to campus on rainy days.
Anyway, all I am trying to say is that it does add up. But I still think Stanford is offering a competitive package to recruit top picks.
Also, having said all that... when I was moving to the Bay Area, everyone warned me about how expensive it is, but I am living a lot more cheaply than I ever did on the East Coast.