You should check out chowhound.com for restaurant ideas. They are more active than ba.food and you'll see lots of reviews and suggestions. We're not into high rent restaurants particularly, although we did have a memorable meal at Fringale, a bistro South of Market that the French chefs at the Culinary Academy adore. The food was delicious, the service correct but friendly, the atmosphere relaxed.
As for what to do for a week - go to the California Historical Society and get a book of walking tours of San Francisco. Get a bus pbutt and ride cable cars and busses for a day. Take a foodie walking tour of Chinatown (I mean to do that myself one of these days). Go to the Saturday farmer's market at the Ferry BUilding, natch. Ride the ferry to Tiburon or Sausalito.
I like walking around Russian Hill, North Beach, Cow Hollow, Pacific Heights - but the neighborhoods are too numerous to name. Recently we popped into the SF Art Insbreastute on Russian Hill at about 9 pm on a Saturday night, wandered around the edges of a truly fabulous rooftop wedding, wandered through the halls to a courtyard with a Moorish fountain, looked at art in studios and galleries, gazed at the sparkling lights on the Bay from the roof. It's a special place, and the cafeteria (great views) is open to the public. The whole thing is open to the public, seemingly all night long. Don't know how they do it.
You'll want to go to Muir Woods, and if you do rent a car for the day, wander the Marin headlands maybe, or take a bus out there and do it on foot or by bike (warning you, it's not for amateurs).
basic overview of saturated fatFor all of the masochists (and cowards like Bob) who angrily proclaim that saturated fat is healthy and that anyone who says otherwise can take...
A tour to Sonoma would be nice (I prefer it to Napa, Sonoma town is old and walkable and quaint, the winery scene not so vast and honky tonk as Napa) so you don't have to do the driving, if you're tasting.
Don't forget to check out the Mission - including Valencia and other nearby streets - active restaurant scene, including various Spanish and South American restaurants. Mariachis wander at night, playing for tips. I lived in NYC in the old days so I don't find the Mission daunting but be aware that it's very urban and has lots of street people.
Ethnic food I like: fast tandoor and curry places like Naan n Curry or Pakwan - these are local "chains" with several branches; Vietnamese sandwich shops and restaurants in the Tenderloin. But chowhound folks have more knowledge than I do.
You may find it fun to visit the California Culinary Academy for lunch or dinner - call ahead to find out their schedule, they are sometimes closed for holidays, and rarely serve meals on weekends. The main dining room (used to be called the Careme Room, might have changed) is an old theater, enormous, two levels, with glbutted in kitchens in the wings and the former stage. The food is showy and can be uneven but the setting is high energy - 700 chef students create a lot of buzz! It's a fun thing to do, close to Civic Center, the Opera and Ballet.
These are thoughts off the top of my head, from a person who lives across the bay and wishes I could get to SF for pleasure more often. If you want an exhaustive list of what to do there with 5 year olds, ask me.
Leila