Microsoft is running a promotion where you get a $50 Caltex StarCash fuel card (via redemption) when you purchase a copy of Windows 7.
JB Hi-Fi has the Win 7 Home Premium family (triple) pack for $195. Effectively works out at less than $50 per copy. Details of the fuel offer are at http://www.windows7fueloffer.com.au/
I initially wanted to buy a student copy, but it looks like the price is back up to $119 on DigitalRiver (even though it still says $49.95 here.
If you can find a better price on the family pack please post it up!
Nice. I bought one for around similar price 6 months ago - no free fuel of course.