If you're into chocolate you'll love Ghirardelli's, and if you know real gelato you'll appreciate the ice cream they make here too. There were six of us and we shared "The Earthquake". It was very good but I believe it was a little overpriced ($ 29.95 + taxes).
The nice thing is that even if you don't buy anything they'll give you a free chocolate sample at the entrance of the store. As I said, the desserts are very good but at night the place can get very crowded and you may have to wait a while before you find a place to sit down. Anyway, make sure to stop by just to get a chocolate sample!