I usually go in the Santa Monica Mountains since it is local. I can't say that any one section or park is better than another. There were no fires last fall, otherwise I'd direct you to those sites. We don't get large expanses of wildflowers like in drier places, but there are a good many different species. Mid April to Mid May are the most floriferous time here. For someone who wants to sample the Santa Monica Mountains in general, I'd recommend Malibu Creek State Park. The scenery is great and varied, they have restrooms and water, they have the M*A*S*H site, and most of the trails are not terribly strenuous.
