2 weeks isn't enough time to do your trip justice, but if that's what you've got.....
First of all you need to decide if you really want to see New Zealand or not.
Second is a cruise the best use of your time. You will be spending a lot of time in a boat risking food poisoning at every meal.
Next you need to decide the pace of your visit. If relaxation is your goal, then pick 3 or 4 spots and enjoy your time. Do you want to concentrate on the cities, see the outback, visit the indigenous areas?
If you want to see as much as possible as a taster visit for a better and longer visit next time, then cram everything in you can.
Practical things:
Australia is an expensive place to visit. Fluctuations in the exchange rate can take a massive toll on your budget. Accomodation isnt cheap and food will be much more expensive than you are used to.
Unless you are used to driving long distances, air is your best option. Driving on the other side is something that is very dangerous for long trips as the roads can be long, straight and monotonous. You can easily drift into auto pilot and end up on the wrong side or lose concentration.
I will give my knowledge of what i know.
Sydney. A shthole. Of course the Opera house and Sydney harbour bridge are the draw cards, as is Bondi beach. Darling Harbour is also worth a look. Kings cross wont be as grimy as my experiences were in the 80s and 90s. Oxford st is the gay capital of Australia. Public transport isnt well organised and it is a fast paced city. Think New York or London. After 2 or 3 days here i have to get out.
Melbourne. Multicultural capital of the world imho. 50% of the names are non british in origin. Nguyen is the 2nd most common name in the phone book. There are more greeks than anywhere outside Athens, more maltese than in Malta and large groups of Italians, serbs, Croats, Lebanese, turkish, sudanese, chinese, vietnamese etc. The city is beautifully organised from an infrastructure and growth point of view and is easy to navigate through. Trams, buses, trains and ferries all cover the city well. You will have just missed the Aussie rules finals, but be there during the spring horse racing carnival. It is the sporting capital of australia, but your timing will be bad to see it.
Brisbane. Australias 3rd city isnt really suited to tourists, but the Gold Coast which is, is only an hour away. There are nice things to do, but nothing that will knock your socks off. Its climate at that time of year will be perfect. There is a great Koala sanctuary near by and river cruises are well catered for. A lot of Aussies retire here or at the Gold Coast.
Perth. On the opposite site of the country and a 4 hour plane trip from the east coast. Never been there. It is popular with british tourists and has a high percentage of english and scotiish expats. If you go here, you will really want to go as there isnt much outside perth.
Adelaide. Not quite as isolated as Perth, but also nowhere near as exciting. the town is basically dead after 5pm. Called the city of churches, which you will either love or be bored by.
Tasmania/Hobart. The island down south is a joke by the mainland people and inbred jokes are common. Has lovely scenary, but the ethnic diversity common in the other cities is lacking here. Culturally 30 years behind the rest of australia.
Major regional areas:
Darwin. The city closest to asia and has the highest aboriginal population per capita. Very hot and humid. Not much to see.
Cairns/Port Douglas. Great resorts, but as they are in the far north of queensland it is a bit of the way out. Because of the jellyfish the beaches are difficult to swim at.
Sunshine Coast. A big strip north of Brisbane. Noosa is a great place for hippies or the young travellers.
Gold Coast. Tourist capital of australia. Can be seen as tacky, but has great beaches. You can literally walk for miles on beautiful strips of sand. Your visit may coincide with school holidays which means if you want to avoid kids dont go here. Schoolies may also be on ie spring break.
Hunter valley. Great vineyards and newcastle has arguably the best beaches in oz
Canberra. The nations capital is a disgusting place that you either love or hate. Guess which camp i fall in.
Alice Springs. The centre of the nation. Surrounded by red dust and if you want to see indigenous poverty, come here.
Uluru/Ayers Rock. A giant red rock that takes ages to get too, you cant climb and there is nothing remotely close.
Whitsundays. The best place to see the great barrier reef. Beautiful islands, great boat trips and in october will be pefect weather. Airlie Beach is the main town here.
Byron Bay. The hippie/alternative capital of australia.
Queensland country. Many towns widely spread out. Townsville, Mount Isa, Rockhampton, Bundaberg, Toowoomba and Mackay would be the best to see.
NSW country. The most populaous state has many fine inland or coastal places, like Dubbo, Broken Hill, Casino, Orange, Tamworth Also some terrible ones like Wollongong
Victorian country. The great ocean road is a magnificent drive to see the twelve apostles. Phillip Island is great to see the penguins. Ballarat and Bendigo are fun as well.
Western Australian country. Broome may be worth a visit. Outside that vast pockets of emptiness.
South Australian country. Nothing.
Tasmania has a few places like Devonport, Burnie and Launceston.
Northern Territory. Kakadu is beautiful.