OK, wanted to add a few more.
First, all the standard tourist stuff in SF is worthwhile (I'm assuming you know what that is, if not, I can drop them in here). If you do Pier 39, there is one thing a lot of people miss...Namely an old WW II sub is permanently docked down there ( a pier or two over), buy a ticket and do a walk through on it. It will not take that much time and I thought it was pretty enjoyable.
I would also mention the Winchester house. It's reasonably well known around here, but it doesn't get the kind of fame Lombard st or the Golden Gate bridge get. Basically when winchester (of gun manufacturer fame) died, his window went crazy. She thought the ghosts of all the people killed by winchester rifles were out for revenge. So, she built a house designed to trick them into walking into walls, etc. It's basically a crazy house built by a rich crazy person. It's technically in San Jose, but that is only an hour from SF.
winchestermysteryhouseI wanted to also point out the San Diego zoo. Out of my area a bit, but it's absolutely impressive. If you start as soon as it opens and spend all day there, you will leave feeling like you saw a lot and still missed a lot. Not a bad way to spend a day.