WNLOVE
This is a great product that I used myself during my latest RTW Trip. They are the official recommended travel insurer of Lonely Planet.
I found their prices were better then any other insurer I compared prices to.
Also, if you are ALREADY OVERSEAS and without travel insurance because your existing policy ended and cannot be renewed (because you're travelling for more then 12 months like I was) or you never bothered to get one in the first place, then I believe this is the ONLY option for you as no other company will insure aussies who have already departed Australia.
Buyer beware - compare policies across companies and read the fine print. While the Canadian insurance policy is a great product, the Australian insurance policy offers a laughable level of coverage. For example, there is no trip interruption insurance. My travel partner (who is Australian) found this out the hard way when we both made claims for trip interruption.
If you haven't left Australia yet and you are an Australian citizen, I would not recommend World Nomads. There are a lot of better options out there with more coverage. Otherwise, if you've already departed your home country, yes, this is the only option I know of.