Our family went last May/June, using the "Aussie Air Pass" which is also being offered in the current promotion. I think it is an even better deal.
The Aussie Air Pass includes (for a slightly higher price) three domestic flights, and you do not have to return from the same city you fly into. (Those three domestic Australia flights would be about $800 U.S. if you bought them individually)
We went to from the U.S. (Chicago) to Sydney, to Cairns (Great Barrier Reef, we actually stayed in Port Douglas), to Alice Springs (The Outback, where we also did a 3 day ground tour to Wilderness Canyon and Ayers Rock) to Brisbane, and back to Chicago.
It was the trip of a lifetime that I have always wanted to do. (The only thing I would do differently is I would probably go to Melbourne for the last leg of the Australian part of the trip, rather than Brisbane.)
I just checked the price today for the above itinerary (ending the Australian part in Melbourne) and it was a little over $1,600 (which includes the $280 add-on for the Chicago to/from LA part of the trip)
Note to disneylovin24: The East coast add-ons are $200 (select fights to/from JFK), $300 Newark or other JFK, $360 Boston, Orlando, or Miami, and $400 Washington