I know a place...
I know a place where property values are actually higher than Boston. Who'd have thunk it?

San Francisco. It's magic for me. I want to live there. No one has offered to buy us a house. We bought a place in Vancouver, instead...

San Francisco,
My favorite city,
Where the women are strong,
and the men are pretty.

San Francisco is my favorite city in the world... and I've been I've been to a lot of them for comparison. It's got a lot going for it:

"Topology" - great hills and dales. "San Francisco: Go Climb a Street" the T-shirt says. It's a test of faith when driving. You reach the top of a hill and it's so steep on the other side you can't see the road. And you wonder "What if the earth really is flat?"
Ethnic diversity - wide mix of races living in relative harmony... each with their own foods, language and culture. All in one city. Such a deal!?
A level of acceptance of others - both ethnic differences, and support for the large Gay population. I have many gay friends and the concept of there being some place that's actually supportive of them... it's nice. Don't we have bigger "problems" on this planet that who is sleeping with whom?
Great parties - from "US/Japan Taiko (big drums) Festival" to "Bare to Breakers".
Berkeley, which never left the 60's. Wow, Man.

The downsides:

Unbelievable housing prices (and that's after the High Tech meltdown)
Earthquakes. I've been in one in Santa Barbara, another in Tokyo; missed the last "big one" in San Fran by one day. Earthquakes are scary.

What's to do? There's always something. I wander. Since first landing in San Fran in 1986, I've learned the streets, the subways, the bus lines, restaurants, neighborhoods. Where to at 1:00 in the morning ("Orphan Andy's"). So I set out - footloose and automobile-free, and go where my feet take me. I recommend it. Helps work off those super-burritos from the Mission district. 

San Francisco Neighborhoods

What makes San Francisco most interesting for me is its diversity. In 10 minutes you can be surrounded by another culture or ethnicity, completely different from the one your were experiencing a minute ago. While there are many neighborhoods, these are the ones that hold special interest. 

The Castro - Known as the the North American, maybe the world capital for Gays/Lesbians/Transgendered people. If you're not Gay-friendly or at least open-minded, stay home. If you're prepared to question your sense of "norms" head for Castro Station (Muni) and observe regular people going about their regular lives... who happen to be homosexual. THere are a number of "homey" restaurants along Castro Street. There also a Leather Bar (this refers to the occupants' clothing, not the bar itself, necessarily) which we don't see much back in East Hartford.
The Haight - This is the part of the City where the "Summer of Love" took place. I missed that (was a bit young at the time - really). It's still a "retro" kind of place, but the "upper" part (the Haight is split into "Upper" and "Lower") is more gentrified; the lower part more downscale. The upper part also has the benefit ending at Golden Gate Park, a wonderful place for a day or just a lazy afternoon. "Haight-Ashbury" (the intersection of the two streets) isn't all that exciting, although you can get a picture of yourself at the intersection. There's a Ben and Jerry's Ice Cream shop on the corner. How "90's".
The Mission - Headquarters for Latinos, from Mexico and all over Central and Latin America. It isn't the City's cleanest or safest neighborhood (in particular be careful at night), but it's got character, low priced shops and ethnic groceries and restaurants, Taquerias.
North Beach - It's not North. It doesn't have a beach. It's the Italian section of town. Adjacent to the primary tourist areas of San Francisco, it's the place to stop for a cappuccino and biscotti,  or a great Italian meal. While you're in the area, check out the Beach Blanket Babylon at the Club Fugazzi. It's hilarious. 

Touristy Things Still Worth a Visit

By all means, take a cable car ride. You'll have lots of company, takusan no (lots of) Japanese tourists with sun hats and cameras - but it's fun, once. . Lots of company. What they don't know is that you don't have to wait at the end of the line with 100s of other clueless Tourists... you can get on at almost any intersection... and pay on board. Shhh! Seriously it's good fun... once. By the way, the link to "youth hostel" above has quite a few good references in it.

"Pier 39 is the place you want to be, so they loaded up the truck...". Sorry, wrong sitcom. Pier 39 is Tourist Central. Like the cable cars, it's a place not visited by locals much but generally high on the list of first time visitors. There are few bargains to be found, and I think better food is available almost anywhere.

Here are some offbeat, wondrous places:

Chinatown. The largest in North America. Experience Hong Kong without having to change dollars or flying 24 hours.
Japantown. A plethora of restaurants and shops... you'll think you're in Tokyo except there's no subway, and the men don't all wear navy blue suits.
The Haight. The center of the "free love" moment of the 70's, it's still Counterculture Central
The Castro. World Headquarters for Gay Planet Earth. Leave your attitude back in the hotel.
North Beach (warning... there's no beach - you can leave your swimsuit home).
SOMA ("South of Market Area")

There are countless other sites to visit. A couple of my favorites are:

Golden Gate Park
Buena Vista ("good view") Park. Take a jug of coffee and a couple almond croissants, the Sunday Chronicle/Examiner and a friend (if you don't mind sharing your Chronicle)
Walk from the "top" of Powell Street (at California) down to the Bay
The Exploratorium, in particular the Tactile Dome. Geek chic.