Comcast CEO Brian Roberts and wife, Aileen, had dinner with newly named "ABC World News Tonight" anchor Diane Sawyer and her filmmaker husband, Mike Nichols, Saturday night at State Road restaurant on Martha's Vineyard. The table discussed "The American Wife," the new novel by Curtis Sittenfeld, who lived here for a few years with her boyfriend. The book is a fictionalized tale of a first lady clearly based on Laura Bush. Sawyer cracked up the table, says our spywitness, with a joke about the "racy" sex scenes in the book. Nichols, whose films include "The Graduate," is quite stylish at 78, rocking a leather jacket and sneakers.