Looking to buy investment unit..been warned about crime areas..where are they?

This question is extremely stereotypical. Areas such as Blacktown, Lakemba, Parramatta and Bankstown have high incidents of crime. But I have friends who live in these areas and they're very happy. I also always go to Parramatta and I don't understand the stigma - the scenery and nightlife there is great.

Gosford is improving in that regard, but Gosford, Wyoming, and Umina Beach have higher than average crime rates on the South end of the Coast, and it tends to get worse the further up you go.
Particularly Lakehaven, Charmhaven, Bluehaven etc.