Pier 39 is pretty nice, if you like shops and food. Especially if your girl happens to be coming along with you. Fisherman's wharf is also good, right next to the pier. Lots of food choices in that area. There's a wax museum and a rainforest cafe if you want to get "crazy." You can also take a ferry and tour Alcatraz if you like.
There's chinatown as well, that's very china-towny.
Palace of Fine Arts/Exploratorium if you're into it. Unfortunately After Dark, the more adult, or rather, non-child themed times, won't be open during your stay time (assuming it's the 23-26).
You also might want to check out the Golden Gate park. Never been there, though, so I can't personally attest.
Mostly just try out the food.