Let me second Tu Lan. The block that it's on is definitely one of the worst parts of town, but it makes a great meal. I'd recommend them for lunch.

Visit the Asian Art Museum.

While on the subject of museums, the new De Young in Golden Gate Park is a must. For a not-tourist cuisine stroll, consider walking Clement Street along the apx. 13 short blocks between Arguello and Park Presidio. You'll find all cuisines of China as well as other ethnic cuisine. Both the DeYoung and Clement St. are relatively close to each other and can be visited in the same part of the day.

For a week, I'd seriously try to include an out-of-town excursion. Stanford U./Palo Alto and the Napa/Sonoma Valleys are reasonably close by recommendations (within an hour or less of S.F.)

Excellent idea! You'd be visiting a real Chinatown, with almost no tourists. Actually, there are probably a couple of dozen cuisines other than Chinese in that stretch. One of my favorite restaurants in the world is a Vietnamese hole in the wall called Mihn's Garden at 3rd & Clement. Also, one of my favorite watering holes with live Irish music is The Plough & the Stars at 2nd & Clement.

I lived in the Inner Richmond for seven years and loved every moment of it.

Foodie?

Do my quintessential SF lunch:
Public transit to Fisherman's Wharf, buy a sourdough baguette from Boudin's, walk over to the crab vendors and have them boil you a fresh crab while you wait. Have a shrimp cocktail standing while he boils, cracks, cleans, and wraps the crab. Take the package and walk around the corner to the news stand. Buy a paper and a bottle of good local beer. I prefer Anchor Porter, but my usual date insists on their Steam Beer. Sierra Nevada or Marin Brewing make some nice libations as well. Walk West on Jefferson about two & a half blocks to the viewing platform on the right, where you can go up to the second deck and spread your newspaper as a tablecloth for you crab feast. What...
Good crab, good bread, and good beer in the fresh air is not your idea of a lunch?
What are you.....a Philistine?

I second the recommendation for Zuni...good California/Italian.
And I also recommend Farrallon (the restaurant...and the ocean viewing trip mentioned by someone else in this thread).

If you have a car (or want to take public transportation)...go to the free art museum in Stanford. You can take walk around campus (it's huge) and visit the free museum (which also has a free sculpture garden).

I have several suggestions.

On a weekend, Saturday mornings at the Ferry Building Farmer's Market are a treat. Snosh your way through the organic specialties, eat at one of the outdoor stalls, or for something different, eat at The Slanted Door (impossible to make reservations at, but showing up on-site can work out well...).

From there, take a ferry across to Sausalito--the ride isn't as long as it is if you do the 1-hr harbor cruises from the Wharf, but the views are just as good. Meander around the shops and views at Sausalito, maybe stay for dinner.

If you go to Wine Country, be sure to drive along Silverado Trail in Napa (more scenic than the main route, and runs parallel to it); and, take highway 12 through Sonoma for some pretty views.

The Charles Schulz museum in Santa Rosa is a good stop fo Peanuts fans.

On Sundays, take a stroll along Embarcadero to Townsend Restaurant for a nice brunch--they're always packed, though, so earlier is better here, too. Tip: If you just want their breakfast eats, go on a weekday morning--much emptier.

For the total meandering experience, get a rental car and drive along SKyline Drive instead of 101 or 280...it's quite different, and has some beautiful mountainous views.

I'm sure I could come up with more if asked. PM if you'd like.
M

All good suggestions so far.
I'll second all the restaurant suggestions so far and add:

Koh Samui and The Monkey (4th and Bryant?--Brannan?) for Thai.
Specialities Bakery for the Poppyseed rolls for Breakfast. (numerous locations, mostly downtown, one of which is right outside the Montgomery MUNI/BART station)

Cafe Flore' in Castro for Weekend Brunch and people-watching.
Greens and/or Millenium for vegetarian/vegan/organic foodie-friendly "California Cuisine". (Both are $$$ last I checked but well worth it)

Twin Peaks for the peaks themselves. Not just the Tour Bus turnaround/overlook place. Climb the peak(s), note the seismic stress lines/patterns in the strata, get a 360 degree view of the City and the whole Bay Area .
Sutro Park/Baths for a different view of Ocean Beach and to watch the hawks chase each other around and hunt for lunch/dinner.

Monterey. The Aquarium is a must-see.

If you're into hiking, I'd recommend Angel Island. If you're into meandering, I'd recommend the arboretum at GG park.

Let me also put my recomendation in for the Zuni Cafe on market. My partner and I love it so much we try to make a monthly visit.
It reminds me of Babbo in NYC. Casual atmosphere, but consistently great food with warm attentive service, and half the price.
Reservations can be tough...
I would sign up for open table.com and book on line.

Another food recomendation would be Ebiusu for japanese food.
I think the Sushi is the best in San Francisco. Go early or be prepared to wait.
It is at 19th and Irving, out from downtown, but the N judah tram, will drop you
at the above intersection.

Almost all of my trips to SF include dinner at Delfina in the Mission. Dining solo I just pop in and ask for a seat at one of their two counters, but if you need a table for two or more you really need a reservation. Food is more Mediterranean than Californian.

If you go to Berkeley, I recommend Chez Panisse Cafe over the main restaurant downstairs for two reasons, a choice of what to eat and much lower prices, for the original and best Californian food. Arrive early enough to get a snack at Cheeseboard then wander around or shop before dinner.

CityPass may save you some money if you're going to several museums, plus it includes unlimited cable car rides for seven days.
http://www.citypass.com/city/sanfrancisco.html

I had the concierge at the hotel make all my reservations for me, including Zuni. He had them done in less than 15 minutes!

After you visited some of the above heres a few more of my personal favorites.

Both SOMA ( South of Market St) For dim sum - Yank Sing still one of the best around.
Coco 5000 considered by some foodies among the cities top ten (or higher) eateries.
inventive, California cusine.

Gary Danko - near Lombard/Hyde great upscale fixe prixe dining.

Visit the Cable Car Museum much more interesting than it sounds.

Wine country - Somoma very good restuarant right on square - The Girl and the Fig.

And two of the best in the entire area ( including the city)
In the neat little town of Healdsburg - north of Petaluma but still in the wine reagion.
Cyrus and Dry Creek Kitchen both far better than any restuarant you will find in most major cities.

mike

Zuni is quintessential SF IMHO. But if you read chowhound, you'll see it garners a lot of debate. It seems people either love it or hate it. I love it.

Surprised nobody has mentioned Tadich or Sam's Grill as other SF institutions to try.

Nopa at Divisadero and Hayes is a fantastic and not too expensive spot for California style food. Getting a res is not so easy, however.