I personally retain points for international flights and \ or upgrades as flying here is usually pretty cheap especially if your flying only the golden triangle.
An important point to remember as well is that these many programs charge a hefty "fuel surcharge" for international flights which can be up to 50% of the fare. At the moment to/from Europe that is around $800 if using Qantas or Singapore Airlines, but varies depending on the airline. So awards flights are hardly free any more, and that's why some use them for upgrades, although getting upgrades can be difficult if you don't fly frequently enough to achieve status.
If you do not wish to use a points earning credit card, and only fly infrequently in Australia (<6 round trips per year) the wisest advice maybe to focus on getting the best fare you can, rather than earning points in one particular program. The dollar savings may well outweigh the value of any points you earn (although I would still join both Virgin and Qantas programs for flights, as there is no cost to accruing them if they happen to offer the best fare of the day).
Having said that:
1) If you do travel overseas frequently Emirates may be an option, although it will take some time to build a balance - as they have low fares and low taxes on redemptions.
2) If you are interested in an Australian based program/credit cards, my advice would be to look seriously at Virgin. You can get a credit card that allows transfers to a range of FF programs (as well as various vouchers), including Virgin. If you go with Qantas, unless you are a high spender you are pretty much locked into Qantas points only with credit card spend - and really at the whim of what they may do in the future. Also at the moment you can get an award booking using Virgin points (on
Etihad) to Europe only having to pay $200 in taxes, whereas Qantas charge $800- and both around the same number of points.