I loved my time in the city. It was so beautiful, I underestimated the visit. I would have to say my favorite moment was walking along the Golden Gate Bridge and hiking up to Vista Point. The whole thing took less than three hours and gave me such a proud satisfaction. There are points that are terrifyingly high and windy but it's just a moment to pass to the beautiful top.
Quick Tips:
There are tons of advice for cheaper rates and discounts for things. You can get postcards 10/ (but post offices are hard to find) and souvenirs are cheaper with each store. The Ghirardelli chocolates are expensive at the actual store but cheaper at a Walgreen's. The restaurants are always offering a deal or special, as well as the boat cruises.
Book Alcatraz in advance (minimum of a week!!!) http://www.blueandgoldfleet.com/
A map is handy for the area in getting around. You can get them at practically every corner, as they are offered free in newspaper boxes. The maps are a part of the San Francisco guides.
http://www.sfvisitor.org/
Best Way To Get Around:
We only took a taxi once, and that was because of an emergency time limit. Otherwise, we totally took advantage of the for a 7-day or for a 3-day city transport pass. It allowed us to use everything from the buses, to the cable cars, to MUNI underground line. The only thing it didn't include was the BART system to the outskirts of San Francisco. Walking was nice but got tiring, so transport at every street was handy. It was because of our pass that we got to cover so much ground on the trip and see so much! A bus tour isn't necessary at all unless you only have a day or so in the city. http://www.sfmuni.com/fares/passvend.htm