I am headed to Australia for vacation. Any suggestions on where to visit or things to do?

If You visit Melbourne you must spend some time on South-Bank and go up Eureka Tower, which is the World’s tallest residential building.
While you are at South Bank, you should make sure you are outside Crown Casino on the hour after dark, because they have an amazing flame-thrower type display that goes off from the top of massive columns lining the Yarra River. There are also some fountains, but they are off sometimes because of the city’s water supply issues.
If in Sydney, do the bridge climb during which you walk up one of two metal staircases to the top of the Sydney Harbour Bridge. The Zoo is also great, if you go be sure to catch the ferry and instead of getting onto a shuttle bus to the main entrance, walk to the bottom entrance and avoid the big queue and massive crowds.
Ballarat is a mining town in central Victoria, which is home to Sovereign Hill, where there is a theme-park type living museum filled with actors which replicates the old mining town. There is a special night-time show called Blood On The Southern Cross which tells the story of the Eureka Stockade, a major milestone in the democratic and Labor movement history of Australia.
If you are visiting Queensland, definitely try and get to Noosa, while there you should try and make it to the Buderim Ginger Factory, which is a bit inland at Yandina. Compared to the Big Pineapple, this place is pretty cool.
Tasmania is the little rejected island at the bottom of the country, but it was the first State in Australia to ban smoking in enclosed Public Spaces long before the UK and all those other places, but it is home to some of the most amazing natural World Heritage sights such as the Lake St. Clair National Park and The Hazards, a mountain range on the East Coast. If you are in Hobart, take a walk through Battery Point and look at Kangaroo Bluff on the eastern shore of the river. It was part of the defenses for Hobart back when it wanted to kill Russians…
The best views of Hobart (unlike most of Australia, it has hills!) are from Mt. Wellington, or Alexandra Battery, another old fort.
I’ve never been to Adelaide, Darwin or Perth, but I can recommend Broome, a town on the North-West coast which is famous for it’s perl farming.
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It’s kind of hard to suggest things to do unless we know what cities/places you are visiting…

I’m visiting Noosa, Melbourne and Sydney, but I’m open to other places along the way. Thanks

It is questioner and not skfinkel who is going to Australia. Just to keep the record clear.

If you’re going to Sydney and are looking for some places to stay on the cheap, check out these Sydney backpackers and youth hostels. There’s a few great suggestion there for under $30 a night, right in the centre of Sydney. And as bluemukaki suggested above, the Harbour bridge climb is awesome! Well worth the view! ;)

Sydney, Melbourne, Daintree rainforest, Great Barrier Reef, Uluru (Ayers Rock).