San Francisco has some of the best public transportation around. With Cal Train and Bart to get you into the city and Muni or the various streetcars and buses to get you around within, it's easy to plan an evening out in Golden Gate City, even if you're coming from Santa Clara.
But, if you're headed to the Sunset or North Beach this winter, you may want to call a cab to travel to your destination quickly and warm. Try the Yellow Cab company: (415) 333-3333 or for a more environmently friendly option, call Green Cab: (415) 626-GREEN.
The city is literally crawling with taxi drivers, so keep your eye out, check the corner of the Cal Train station at 4th & King, or call a cab in advance.