300 billion as part of a 20 year plan...
http://www.news.com.au/story/0,27574,25417217-5012587,00.html
I'm not sure we need all of the things mentioned. Perhaps Kennas or some of the others who have served could give a more realsitic view.
We easy spend that much to keep the welfare underclass living in free accommodation to watch the cricket and drink beer while the rest of us go to work. About 60 % of the annual Australian budget goes on welfare, amongst the highest in the world. If we got all of those people off the couch and working, taxes would be very very low in Australia.
The point being, that we already spend far more than this on useless things - and defence is useful and a very good investment in our future.