San Francisco
San Francisco has been called the most romantic city in the world. It's easy to discover why so many people have fallen in love with "The City." Between the mild weather, the variety of scenic vistas and the plethera of things to do together as a couple (museums, theater, dining, nightlife), you may want to extend your trip.
San Francisco is also a great home base in which to travel up to Napa (less than an hour) and down to the Monterey Peninsula (about 2 hours).