Trattoria Contadina was our neighborhood Italian place when we lived in San Francisco and recent visits confirm that standards are still as high. The food is mostly traditional italian with a continental flair. The ravioli is handmade and melts in your mouth. Service is impeccable. And even the house wine is unusally good.
Definitely make reservations. This small space is always packed. There is an upstairs room for larger parties - not as pretty as the downstairs space, but very functional. Oh, and once you're a regular, expect little freebees :-)