The wharf is a tourist trap, but it can be a lot of fun too! I would try some of the smaller restaurants in the Mission or Nob Hill districts. Also try some of the places in the South Park area of SOMA, they're very cute.
Sometimes a simple buffet can serve as a godsend for large groups. The Filomena Ristorante is perfect if a touch of Italian cuisine strikes your fancy. Parked on Wisconsin Avenue and serving up just about every Italian dish you can think of, it's a great stop. If Italian doesn't strike your fancy, there's always the La Chaumi?re on M, which serves up French food.