Caffe Greco serves the best cappucini and caffe macchiati this side of the Atlantic. They use Illy caffe, and every barista there knows how to work the expresso machine perfectly, right down to making the heart-shaped pattern on the top of the milk froth.
They also serve many great desserts and gelati. Those looking for a light meal can order an insalata caprese or one of their many focaccia sandwiches. But the highlight remains the coffee.
There are other decent cafes around- the neighboring Caffe Puccini, Steps of Rome, etc. But personally, anytime I am in North Beach and in possession of $1.65, I head to Caffe Greco for a caffe macchiato.