Sydney is a great city. Looks like most Europeain big cities, but has better wether. ;) You can get anything you want, plently of parks, pubs, resturants of all kinds, night clubs, museums, simply anything. It is also just cool to walk around the CBD (Central Business District) and cross the harbour bridge (Although there is not much on the other side, but it is worth the walk).
Insider Tip:- Go to the "I am free" tours at 18:00 next to Circular Quay. It starts like school trips with history, but gets really interesting with stories about gangs from the time it was a prison colony and such. - The places that sell traveling trips have computers with internet that you can use for free.