While there's no denying that Sydney is incredibly expensive, it is most definitely not a dump as some people have mentioned on here.
"Oh the roads are so busy" -- what do you expect in a major city?
Shoo, as people have mentioned, the Sutherland Shire is definitely one of the nicest areas to live in and isn't too far from the city, although some/most areas are expensive. However, if you go just out of the Shire to places like Engadine, Wooloware etc. the properties are much more affordable. There's also a lot of parks, and plenty of shops etc.
I live near the city (15 mins-or-so away) and the missus lives in the shire so I travel there quite a bit at all times of the day/week, and whilst the traffic is bad, it's not as bad as some people are whinging about on here. It's only ever 'frustrating' when there's an accident, because for some reason that's when 85% of drivers decide it's time to drive at 5 km/h so they can catch a glimpse of the accident.
As sax mentioned, I think it's a good idea if you and/or your partner can come down for a weekend to drive through certain areas and experience them first hand.
Good luck.