North Beach is a great place to live if you are single and in your 20's or 30's. I could not imagine trying to live their with kids--high rents, busy streets, lots of people getting drunk at night, small apartments... Maybe if you have one kid.
If you have the money--and that is a key factor since kids will add a big expense in addition to the high cost of living--most people find a place in Pacific Height or Cow Hollow. Though, I would go even farther out to either the Richmond or Sunset District and those areas where it is quietier and a touch cheaper.
Imo anyway.