My vote goes for Berkeley. If you can afford it, the north part of San Francisco would be a great place. You could go to Marin AND East Bay fairly easy. Even though SF is always cold, Marin and East Bay have a different climate.
Marin has Fairfax/Bolinas road, which to me is the absolute BEST road to ever ride on. Great climbs, great descents, no cars, and very pretty. If there's someone here that hasn't done that road yet, please do.