I have lived in Australia for most of my life and I must say it is a wonderful place to live. I have not holidayed in many places in Australia. We have been to the Gold Coast in Queensland quite a number of times though. Queensland has a great climate (tropical). There is so much to do there. The Great Barrier reef and the numerous island resorts.
We though, only go for the theme parks, as we have two young children.
There is Warner Brothers Movie World, DreamWorld, SeaWorld and Wet & Wild water park all of these are great and cater from the young to the old.
There is also a fantastic new themed show called the Outback Spectacular, which is well worth a look. It is a meal and a show with an authentic outback feel, The food is great and the show is magical. (there is even a helicopter that flies indoors!!!!!) We have been twice and both times where just as great.
Queensland is also home to Australia Zoo, made famous by the late great Steve Irwin. This is also a great place to visit, it is a huge park, very well laid out and very easy to walk around. We did a tour last time we where in Queensland (we try and go once a year), we caugh a coach, it takes about 1.5 hours to get up there from the Gold Coast but the scenery is great.
I live in South Australia, just near the Flinders Ranges. This is also a fantastic spot. It is only a couple of hours from Adelaide and it has countless places to stay and visit, The Clare Valley is a wine growing region and has many cellar doors for wine tasting.
The Flinders Ranges is best seen at this time of year when it is green and cool. The summer is very hot, dry and dusty and the flies will drive you mad.
You would be able to drive yourself around the Flinders Ranges as the roads are great and well sign posted. And there are heaps of places to stay.
We have a property in the Southern Flinders Ranges where we grow olives and make Shiraz wine and breed sheep. It has a slight mediteranian climate. A great place to live
The only other spot that should not be missed is the red centre, Ayres Rock and Alice Springs. This is also a fantastic place to visit, we drove from Pt Augusta and it takes about 12 hours. You can catch the Ghan train from Adelaide. This is a fantastic way to see the country side in the comfort of the train. (Not in the coach section though) it pays to spend extra and have a sleeper, where you have your own room, toilet bathroom and can eat in the dinning car. You can go to Alice Springs or as far a Darwin. This would give you a sample of all sorts of sites. Alice Springs is a great base to do tours out to the rock and other historic sites.
Darwin is very tropical and also has a great war time history.
Hope this helps a little