Should I drive my car to the Bay Area for a 2-week trip, or take a flight and use public transport?

Coming from California, driving in Las Vegas and Phoenix was a joy for me. It is not up to Los Angeles levels of awfulness. But traffic in the San Francisco Bay Area is still pretty terrible by Southwest standards. The lack of free parking, narrow roads, and rude drivers make the experience less than ideal.

Though a car is useful if you have free time and plan to visit scenic areas in Northern California (Muir Woods, Wine Country, Yosemite, Lake Tahoe, Santa Cruz, Monterey, Carmel). There are bus tours to all these places from Downtown San Francisco. But it is nice to have your own set of wheels and not have to see everything on somebody's else schedule.

Public transportation is excellent within the urban core. If you don't plan to venture far from San Francisco, Berkeley, Oakland, and San Jose, there is certainly no need for a car. Since you are staying for a couple weeks, it might be a good idea to get a Clipper smart card. Clipper lets you board all the various transit vehicles in the Bay Area without having to buy separate tickets for each.

http://www.clippercard.com/

Could take a flight then rent a car, or you could take public transportation except when you want to make some excursions outside the city on your own, independent of of all the bus tours. Otherwise, it's not so much the traffic as the parking in the city, especially San Francisco.

I live north of San Francisco, where the buses aren't quite as frequent as you might like. In fact, the buses might be seen as a time-consuming hassle. So, if you want to see all the scenic back roads, you might enjoy a rental car, just not in the city. Do some research on the cost of rental cars & consider any discounts, such as AAA or Costco, that you might have on them.

If you have a place to park, and enjoy driving, I'd say bring a car. But that's just me.

Public transportation can be good and traffic can be horrendous. Depends where and when.

two weeks?

drive up there

use public transportation for things in the city while driving to places in the hinterland