The East Coast Grill does an excellent chicken liver appetizer. Jake and Earl's has a similar appetizer although the rest of the menu was a dissappointment. I used to enjoy the chicken livers at Durgin Park, haven't been in awhile.
When I lived in Boston (3+ yrs ago) Franklin Cafe had a great chicken liver dish...perfectly seared chicken livers with fresh grated horseradish. Sometimes they altered the combination, but they were always great.