What I love about California is throughout the state, you run into such a variety of atmospheres and settings in each region; its hard to believe you're still in the same state. I laugh at the folks that are Anti-Nor.CAL or Anti- So. CAL because you miss out on so much each part of the state has to offer.
I love parts of the bay area and so. cal. Even central california (<---yes, i said it)

Its hard to pick cities, so I'll cite regions.
As far as the bay area goes, I think Santa Clara county is nice. I like Gilroy (I got used to the garlic smell when living with my sister) its weather and people. The drive through Pacheco Pass/152W ranks in the top 10 for me. Mtn. View is a beautiful place as well, its almost the perfect location ; near San Jose, not too far from S. Francisco. Shoreline Park is fun to go to, tons of restaurants, and racial diversity is decent. The amount of good jobs seem to be growing. As a child, I spent my summers in Fremont and loved it. Now it seems, Fremont is of pre-dominantly middle-eastern culture, which is fine, but I prefer a melting-pot city. If the wife and I don't end up moving back to the DFW TX area, santa clara county would probably be my choice.
LA - I love the LA area , lived in the San Gabriel Valley for a few months, commuted from Bakersfield to LA for 2 years. Its just that, the middle class is rapidly decreasing; its, either your struggling or rich. Venice Beach and Santa Monica are great getaways for my wife and I. The homes on Venice Beach's boardwalk are amazing.
Bakersfield- Currently, I've been in Bakersfield for 4 years. Its great affordable living thats not too far from the coast and 40 min drive from LA County. The downside is the city is extremely conservative. It's the type of city/town that bans things or events if deemed too offensive. In 2005, they banned "Get Rich or Die Trying" movie from theaters and in June 2008, Kern County placed a ban on courthouse marriages due to the allowing of same sex marriages. Oh, the fact that is connected to Oildale and lacks a variety of adequate post-high school education is a negative.
I hate Modesto even more, Fresno is a little better but not by much. Just my two cents