I own a car, but use it only for driving to meetings (where a bike jersey is not the appropriate attire), shopping, or leaving town. The transit system here is very good, and the bike lane system is getting better all the time (the bike lobby has growing political clout in the city). Also, parking is a &^^ as the city uses tickets as a big revenue stream, so if you are illegal for only a few minutes, you'll get a ticket. You will also save time by not having to park.
The downside is that the Muni rail system is not entirely reliable. Normally it takes me 30 minutes from door to door via Muni (N line - when it's raining which isn't that often), but it can take up to 50 if there is a problem which is about 20% of the time. (Biking takes me 20 minutes or less). Of course if you work out of your apartment, commuting is a non issue.
The downside is that the Muni rail system is not entirely reliable. Normally it takes me 30 minutes from door to door via Muni (N line - when it's raining which isn't that often), but it can take up to 50 if there is a problem which is about 20% of the time. (Biking takes me 20 minutes or less). Of course if you work out of your apartment, commuting is a non issue.