SadClown

Bernal Heights is primarily a residential neighborhood. Other than Cortland street, most of the streets in Bernal are primarily residential, and the twisting, hilly layout makes them fairly quiet, with minimal auto and foot traffic compared to the rest of SF. Houses were mostly built in the early to mid 20th century, and being on a hill, many of them have spectacular views. Bernal dwellers have a definite sense of pride in their neighborhood, and it almost seems like a small town plunked down in the middle of San Francisco. If you feel like stretching your legs, hike up from Cesar Chavez or Cortland to the top of Bernal Heights park and enjoy a 360 degree view of San Francisco.

Orange Alley is a small side street running parallel to Valencia. If you're looking to move into a flat or apartment that looks out onto Orange, be aware that there's a window shop that runs saws and woodworking equipment, sometimes on weekend mornings, and a funeral home that can often have a lot of traffic.

Most of Corbett Avenue winds through the hills, parallel with Upper Market. The high-up location gives you one of the best views of the city, and there's very little foot or car traffic, so the street is fairly quiet and clean by San Francisco standards. The drawback is that, unlike much of San Francisco, you don't having corner stores, restaurants, cafes and bars within a few blocks walk. You can still get to the Castro or Portola districts on foot, but it will be a bit of a hike. Parking also gets snapped up quickly, and bus service isn't as good as in some parts of SF.

Marin Street is located in San Francisco's industrial hinterlands. The section between Indiana and Tennessee is home to a lot that holds old San Francisco MUNI vehicles. In back of this repair yard (down Indiana) is a skateboard spot that's become legendary among street-style skaters. If you're the kind of urban explorer who loves finding strange, abandoned weirdness, this should be on your short list.

This is a short street down by the waterfront, and doesn't have anything like restaurants, bars, or businesses. If, however, looking at strange, decaying industrial areas is your thing, it's in a neighborhood that offers some interesting sightseeing. This whole area is almost abandoned on weekends, so hop on a bike and go riding around to view San Francisco's soon-to-vanish industrial past.

Bartlett street is between (and runs parallel to) Mission street and Valencia street, so you're steps away from a very vibrant part of the Mission, but have somewhat less noise and traffic, and even somewhat cleaner streets. The Mission Library is located at 24th and Bartlett - if you're riding your bike, to the library though, be aware that there have been frequent bike thefts from the bike racks in front of the library.

26th Street in San Francisco traverses several neighborhoods. Running west to east, you go from Noe Valley, through the Mission, and past the housing projects by Garfield Park, so the character of the street can be radically different depending on where you are. Although it's primarily a residential street, some notable features include the Dovre Club (an Irish bar at 26th and Valencia) and a city-run public pool at Garfield Park.

Dorland is a residential side street located in San Francisco's inner Mission district. It's fairly quiet for the neighborhood, but very convenient restaurants and shopping on 16th, Valencia, and along 18th. One drawback, though, is that parking can be hectic. Those visiting Dorland should be aware that it runs for two blocks between Noe and Church, stops, and then starts again between Dolores and Guerrero.

Prosper Street is a fairly narrow, one-block street between 16th and 17th streets, not too far from the Castro. Being essentially an alley, it has less traffic than nearby streets, and it's lined with well-kept older houses, albiet ones built on tiny plots of land. Those considering moving there should be aware that although it is quieter, it still gets a good deal of foot traffic, especially at night, and the public health center on 17th and Prosper does tend to draw a number of loitering homeless.

Manchester Street is a two-block residential street heading north side of Bernal hill ("north face" to the locals.) Despite being only a block off of Folsom and a few blocks away from noisy Cesar Chavez street, it's quiet and fairly traffic-free at any time of the day or night, yet close by the Mission. By the way, did I say it's steep? If you live nearby and park there, be sure to pay attention to the hand-painted space markers designating parking spots or one of the residents may leave a note on your car informing you of local parking etiquette.

As other posters have mentioned, Bryant street runs through several neighborhood. I'm focusing on the section in the Mission (which I'll very broadly define as the part from Cesar Chavez to 16th street.)
Much like the rest of the Mission, it's a mixture of long-time residents and businesses and newer arrivals, so you can find shops like Rancho Grande used appliances and then restaurants like Blowfish Sushi. There's usually a dinner crowd at El Metate, and be sure to check out CellSpace art space.

Tiffany Avenue is a one-block street that, although very close to Valencia and Mission, is quiet and has relatively little traffic due to it essentially being a dead-end street. It's a convenient neighborhood, close to public transport and Mission Street businesses, and may be overlooked by those put off by the hustle and bustle of the Mission.

I'm reviewing the north part of San Jose Avenue between Cesar Chavez and the entrance to 280. Although more of a residential street and a route to the 280 freeway, it's convenient to both Noe Valley and the restaurants & bars on Mission street. One standout local business is Mitchell's Ice Cream at San Jose and 29th, where you can find long lines day or night for ice cream in flavors such as baby coconut and Mexican chocolate.