Honestly if you want to be safe stay out of the Tendernob. Don't go to the Bayview and avoid the projects. If you can follow those rules you will be introduced to one of the most remarkable cities outside of Europe. If you can't then might as well be in East L.A. If you are into food, nightlife, entertainment, sight seeing and proximity to the mountains then SF is your place. The kicker is that you won't want to leave. If you enjoy exploring your neighborhood just go for a walk and you are sure to be entertained. My wife and I go on weekend walks and just emerge ourselves in whatever neighborhood we chose to explore.