The Marriott downtown is probably your answer. The Stanford Court Ren is probably a bit nicer but is very much geared to a pretentous weekend on Nob Hill. Kids won't want to walk the hill and the environment is very stuffy. The Marriott downtown (I live 1 block away) is definitely a business hotel, but it is also one of the better standard Marriotts systemwide, the exec lounge has an excellent city view, and the restaurant isn't bad. It is about 30 feet from Metreon, which is great for kids as it includes SF's largest movie theater, food court, all sorts of Sony and gadget shops, an arcade, etc. It is part of Yerba Buena gardens which also includes a zoo muesum that I've never been to, bowling lanes and ice skating.

Granted, it's far from the Wharfs, but it's a few blocks from the cable car and even closer to public transport. It's about a $10 cab ride, too. The Wharf properties are all so run down and white trash at this point that I would sooner stay at the airport. That part of town is going to become overrun with tourists soon, too, as the whether is finally turning beautiful.