If you want more comprehensive advice post on the equipment forums at
http://bushwalk.com/forum/index.php . Its an aussie forum with long range hikers and expeditioners. They know a lot more about gear than hunters usually.
I personally use the cheapest thing I can find on any outdoors shop shelf myself. I dont usually use one at all at low alttitudes, like a few of the fellas here in North QLD you don't really need to. But on the tablelands or just hiking some of the taller hills like Bellenden Kerr or Bartle frere it can get cold in winter, and they bloody rain 300 days a year too. I'll resort to a fleece and cheap shell as mentioned on those occasions. I brought a few fancy parkas home from overseas by 5-11 and Northface but the wet season mould found their space age coatings very tasty and they only lasted about a year.