Big Sur, Point Lobos to San Francisco is excellent, what I like is how little Point Lobos was allowed to change, only nature works there. Yosemite would be great if you can get there or in and around San Francisco and even north to the Redwoods. Too little time and too much to do, isn't it always that way? California is like an entire country.
I was toying with the whole idea of the "Nostalgia Tour 09" and checking off locations like Oceano, Point Lobos etc that have a strong photographic resonance but I believe some of these places ain't like they used to be?