My vote goes for the Japanese restaurant, Ebisu, in the SFO International Terminal Food Court on the boarding gates G side. The original full-service restaurant in San Francisco proper is one of the SF Chronicle's Top 100 Restaurants--five years in a row. It also rates as one of the top Japanese restaurants in Zagat's SF guide. Of course the airport outlet is not as full service as the main location, however, it still has a sushi chef making great sushi and serves great bowls of udon, teriyaki and other dishes.
If one is hungry and has time to spare before, during connection, or after flights, Ebisu is definitely worth a trip on the SFO AirTrain that quickly connects all the various terminals.
As an additional SFO perk, obtain two hours of free (validated) parking in any Terminal Garage by spending $20 at any participating International Terminal restaurant or shop.
A link to the SF Chronicle's reviews of Ebisu:
http://www.sfgate.com/cgi-bin/listin...nue?vid=181322