I bought the Home Premium on release day and was pleased to find a 3 licence upgrade called "Family Pack " for an extra $85 bucks...
What pisses me off is that I wanted to go the 'Family Pack' route to install on 3 PC's, but MS decided in its "let's get Win 7 on as many PC's worldwide as possible" wisdom not to make it available here in Oz. Hmmm, that makes "let's get it on as many PC's as possible" sense. 
Oh well, I ended up getting 2 copies of Home Premium (one for me, one for the missus) @ AUD$129 each... less 5% discount for cash, but Win 7 will not be going on the 3rd PC now, not in the absence of an Oz 'Family Pack'. Vista UltimateSP2 x64, which has been running great on a lesser rig, will go on there instead.