Is my 2nd time coming to Sydney, it was excellent trip! 1st time going "inside" the opera house and watch an opera, that was a great experience! Also watching movie at the world largest IMAX was awesome!
Insider Tip:If you have an extra few days, definitely make a trip to Canberra (only 3 hrs drive), also if u like skiing, I think people go from Sydney to Canberra then into the snowing mountain for skiing! So definitely check it out!