Nice is difficult description. I love where we live - I would choose Enmore/Newtown/Stanmore. Near to everything,can walk to cinema and train station, tons of restuarants but very pricey these days....5 kms from city.
I love being near the ocean, so for me the northern beaches - Manly, Collaroy, Dee Why are the ideal spot. Lots of beautiful beaches and parks to choose from on the weekend. Also plenty of cafes / restaurants and shopping centres to choose from.
Nice means bias. If we're happy with where we're living, then of course our suburb is going to be 'nice' and 'safe.' My current (top five) hit list, in order, and of course my current suburb has to be first:
I like being inner city and not too far from the beach so for me the Eastern Suburbs. There are many nice suburbs to live in Sydney here is my short list: Woolhara, Vacluase, Watsons Bay, North Bondi, Bronte, Potts Point, Surry Hills Paddington. Northshore: Mosman and Manly
I live in Newington, the place they used to house the athletes during the Olympics which was converted into a suburb after. There are many, many young families living here and it is a very nice suburban neighbourhood with lots of young kids and very culturally diverse.
I live In the Sutherland Shire, which has the only beaches with a railway station!
Although I don't think it's affordable anymore, it would be a lovely place for young families. with lots of schools, 2 hospitals, kids parks, the Royal National Park, & a recently updated Westfield's!