KneeHighBoots gave you lots of very good suggestions on what to see, but there's lots more to see, too. I usually tell people that if they have the time available, plan on spending two weeks here. That will give you enough time to see most of the interesting and popular places, but you still wouldn't see everything.
So plan to spend as much time as you have available for your trip.
When you know the dates you'll be here, let me know. I live near the Castro and would love to get together with you for lunch when you're in the area.