I was there for 3 days early last year (see the articles section for some pics), really enjoyed all of it, walking around the castro and mission area, we walked from fishermans wharf back all the way across the city to the market area where we were staying which was cool, up and down lots of hills past the curvy street etc.
cycled across the bridge to sausilito and got the ferry back, all very touristy but all great and lots to see just walking about.
enjoy!
One thing is be careful of the popular trams at popular times, queues can be an hour plus....