My wife and I will be visiting San Fran. in December for the first time. We will be staying four days and we would love to chow down on some really good food. With so many choices, we have had a really hard time narrowing down where we want to eat. Thus, could anyone rec. any great places to eat? We are really open to any type of food in (almost) any part of town. We would prefer casual dining, but if there is somewhere that is amazing, we will certainly hit. Thanks so much for your imput!