You must be excited! It's a big country, so I guess the main thing to ask is where will you be based? Also, will you be able to travel much?
There is a website at
www.australia.com that gives you an overview of the whole country.
Personally, I think the two most beautiful areas are Tasmania and North Queensland.
Tasmania because of it's history and the small town feel, even in the capital city. North Queensland due to the amazing natural phenomena. It's ana mzing place for a holiday. The Great Barrier Reef and islands scattered along the coast is not to be missed. I see you have a website that mentions the Daintree. Very beautiful up there. Cassowaries (endangered) can often be seen crossing the main road. Amazing birds. Rainforest meets the sea and the beaches are incredible. One problem... you can't go swimming in the ocean safely up there during the summer months (which will be when you are here). This is due to stingers or jellyfish. I'm not sure how many tourist companies make this clear before someone comes over. The dates are between November and April. Even so, it's a beautiful place to walk along the beach and there are some walking trails into the rainforest as well.
Around the Cairns area, you have dozens of bushwalks, boats to the islands and reef, a skyrail trip up a mountain into the rainforest village of Kuranda and the Tjapukai dance theatre which is an amazing show put on by the local aboriginal tribe. The city itself is ocean side.
If you want to be in a pristine natural area and see tons of crocodiles, head for the northwest and Kakadu National Park. Lots of accomodation there and the most magnificent wild mountains, waterfalls, rivers imaginable.
Hope this stirs up the excitement a little. If you can tell me the general area you'll be staying, I'll be able to tell you more.
Have fun planning.