One of my absolute favourite San Francisco restaurants is Ozumo. It's modern Japanese, sushi and wonderful mains. The best thing (and the most expensive thing) on the menu is the Kobe beef, which is about $100 for six-eight pieces about the size of the space when you touch your thumb and forefinger.
It is completely worth it. You will need to share it between multiple people as it's so incredibly rich. It will make the meal for you. Extraordinary.