My place is located in the heart of Sydney CBD, you will find it super convinient. Not only it is convinient location, you will also find it quiet at night. (Not many city apt are quiet at night in Sydney)
You can walk to Darling Harbour within 10mins and to Opera house it takes under 15mins walk. City shopping mall is less than 5mins walk distance if you love shopping, trendy bars and restaurents(whether it's cheap meal or fine dining) are so close by whithin all walking distance.