Depends on what climate you want and also what time of year you wish to travel. All of Australia is beautiful during any part of the year. I really like tropical locations such as Queensland and the top end of Australia, but I cannot handle really high heat, so winter in the tropics is really beautiful I think. On the other hand, I am originally from Hungary, have been living here since I was 11 years old, so I do miss having the winter snows I used to experience when I was a kid. A few years back I got to experience Tasmania during the winter months, we traveled there during those months so I could experience snow again, of course it snowed for two weeks before our trip and did not snow at all during the time I was there, but it was still pretty awesome if you like that kind of climate.
When do you plan to travel and where are you from?