I have had a car here in SF for the last few years, and only use it to go shopping, or get out of town. Last month I picked up a little motorbike - it is super convenient in the city. Parking everywhere, and for the most part, motorists are fairly contentious.
I liked my motorcycle for city riding, but I didn't have the nerves to ride on any of the surrounding freeways so I got rid of it. Something like a Vespa would be amazing in SF.