We had two longtime California reporter/forecasters answer this one:

Adam Wright:

I guess I would pick 2 areas -- one realistic and one not so realistic

First the unrealistic one: I would probably want to live around, and have access to, the Ranch. First off it has several good breaks all with limited public access. Second it picks up a mixture of both Southern Hemi and North Pacific swells. Third, and almost the most important thing necessary to consistent rideable surf, is that it has great orientation to the wind -- NW winds (the predominant California wind direction) blows offshore to side-offshore for many of the spots. Another good reason is that it is a great homebase for surfing the other areas nearby. No matter what the swell direction you can pretty much find a break that will pick it up within a couple hours drive, if not closer.

The more realistic (and much more affordable) choice would be Northern San Diego County. There are many of the same properties as my other choice: there are few good breaks spread throughout the area, Trestles and Swami's are both solid waves (crowded but with great shape). Second, it can pick up both Southern and Northern Hemi swells -- in fact, it is a bit more exposed to the Southern Hemi (check out the SoCal Swell window poster and you will see what I mean) so there is more good activity in the summer. Third, the water can actually warm up for part of the year. If conditions cooperate you can get some pretty nice water temps through summer and parts of both the spring and the fall. Fourth, it is another good homebase -- f you are not completely exposed to a swell you can get to somewhere that is pretty quickly, traffic permitting of course. As a bonus you are also pretty close to Baja so you eliminate some of the headache of getting south of the border.

and Kevin Wallis:

Assuming crowds are not a factor: San Diego County.

The County of SD has the most wide-open swell window of all the regions of Southern California. It can pick up anything from SE 165 degree and above Hurricane swell/Southern Hemi swell (Point Loma, Coronado) to NW 300 degree swell, so there is almost always something to ride from IB up through Trestles. You have a variety of different types of breaks: lots of good reefs, decent beachbreaks for the wind swell/combo swell days, and a great deepwater canyon beachbreak (Black's). While there is a tendency for the area to get blown out from prevailing W to NW wind you have an option that is at least semi protected (the Cliffs with the kelp outside can help to keep the chop down at least a little bit). It will be offshore in NE, E and SE wind with a good S wind alternative in the Scripps/Shores area. I really like to body surf as well and there are a few good dumpy/hollow spots for that: the Windansea shorebreak and Marine Street. Climate is a pretty big factor for me and SD is tough to beat with lots of sunny, mild days plus the water temp (especially in La Jolla) has a tendency to be as warm or warmer than any other spot in Southern California in the summer (often in the upper 60's to low 70's).

Santa Cruz and The Ranch would be close seconds as they both can pick up a variety of different swells and are offshore/protected in the prevailing NW wind. SD wins out primarily because you can get away with trunking it at least a couple of months out of the year.