I grew up near Jackson and have spent a bit of time in a few of the wine regions you mention.
The Hunter is my favorite area in Australia, although it has started to get more traffic and is a bit more commercial than it used to be. That being said, it is a perfect 2-day escape from Sydney. There are some really lovely hotels and the valley is picturesque.
I recently visiting Martinborough in NZ and I can tell you that I felt "at home" in the area. In some places (and if you ignored the water views), I felt like I was driving through Wyoming. I was there during the off season but Martinborough felt like a smaller and less touristy wine region. I liked that it had amazing wines but was not one of the "big" wine centers that is on everyone's list. Everyone was incredibly friendly and the wine tasting was very laid back. It's also worth stopping in Wellington for at least a day on your way to/from Martinborough.
I love Shiraz, too, and I left Marlborough with a case of some really, really amazing and unique Shiraz.
Last edited by jja34-1; Sep 29, 2013 at 12:59 pm