I would say San Francisco, without a doubt. The other cities mentioned are quite Democratic, but they do not have a political culture nearly as liberal as San Francisco. Politically, San Francisco would be a moderately liberal European city.
No, No, No, No!
San Fransisco would be THE most liberal city in Europe, except perhaps for Amsterdam. SF would easily be contender for the most socially liberal city in the world. I don't know why people think Europe is that liberal. It isn't.
Even London doesn't have the whole huge hippy/gay/counter cultural element prevelent in some US/Canadian cities. Places like Toronto, SF and Seattle are easily more socially liberal than London, and probably fiscally too.
