On a whim I decided to look up the most expensive home in San Francisco on Trulia. Here it is - the $70 million penthouse at the top of the St. Regis Tower. How does 20,000 sq ft (including 2,200 sq ft of open terraces), 6 bd, 4 full ba, 4 1/2 ba, 22 foot floor to ceiling windows, and 360 degree views sound?