Are their alot of differences people can tell?
I think the Bay Area has more centralized downtowns because there are more liberals which can mean more press for conservation of open space and farmland and less urban sprawl.
Planning wise, I also think Bay Area cities and towns are more dense than SoCal cities and towns and that they are better connected with the rapid transit like the BART where as SoCal is more connected by freeways.
I also think the Bay Area towns and cities have more people with a layed back attitude. I also think there are more Asians in Northern California where as Southern California has more Latinos.
Climate wise I think the Bay Area tends to be foggier and have more rain.