In San Fran see the Golden Gate, walk the Wharf, and go to Alcatraz. All worth the time. Also, if you get a chance, catch a Giants game, but go during the day. At night you'll freeze your ass off. Sit in the upper deck, first base side--best view. Also you must head to Muir woods to check out the redwoods, and while there drive on down to Stinson beach. Very cool place. Can do this on the same day you go to the GG bridge (you have to cross it to get to Muir anyway).
There is a really cool bookstore there called Chronicle Books. They publish a ton of really cool and obscure titles there. I've done three book signings there (at the Metreon location), and every time I've been there I spend more than 500.00 buying books and having them shipped home. I LOVE this place. My idea of the perfect bookstore, and they are always very good to me. A truly awesome experience.
I'll post some LA stuff later.