Australia has over 40 official wine regions spanning virtually all states. Its wines were in the forefront of the 1980's revolution in marketing, overturning the European style of labelling wines by the locale of production (e.g Bordeaux) in place of labelling them by grape variety such as shiraz. Australia's relatively predictable climate and modern wine making techniques employed by winemakers that have academically studied the subject leads to high volumes of wine of consistent quality. Again this contrasted with European winemakers that typically inherited vines and were not academically trained, and thus produced more variable quality wines.
The main criticism of Australian wine by non-Australians is the lack of individuality of the cheap high volume exported wines like the chardonnays. It is said they are consistent, but all the same.
While most of the Australia wines available in a UK supermarket are also available in Australia too, there is a tendency that they are the cheaper wines, mass produced in the huge wineries of South Australia. In fact, many of the better and more individual wines are made by dedicated individuals in small wineries producing limited quantities that cannot produce the volumes that would make it worth, say, Tesco or even Oddbins dealing with the producer. Part of the joy of being in Australia is discovering that world....usually by visiting the cellar door.
Being so large, Australia offers a range of growing conditions, however, they generally are either 'hot climate' or 'cool climate' - these terms being of relavance to the effect of the climate upon the ripeness of the variety of grapes. It is generally held that cabernet sauvignon and shiraz do better in 'hot climates' and that pinot noir - in particular - does better in 'cool climates'. The main 'hot climate' regions are in South Australia: McClaren Vale, Coonawarra, Clare Valley and Barossa Valley. Others include Heathcote in Victoria (a rising star of a region) . Cool climate regions include most of the other wine regions in Victoria including the Yarra Valley, and also Tasmania.
 Classic Australian Wines
Ask your average Australian and can only be one answer: Penfolds Grange, which is a shiraz. If an Australian is to own that 'special wine' for that special occassion then this is it. It costs a lot, typically several hundred dollars per bottle. And besides it needs to be cellared for many years before being drunk. A close second in both esteem and price is Henshke (pronounced Hen-shk-ee) 'Hill of Grace', again a shiraz. For chardonnay, Leeuwin Estate's Art Series Chardonnay from Margaret River, WA is often cited as the best, though your average punter probably would not have heard of it.
Increasingly Langton's Classification of Australian wines is being used as some kind of definitive A-league list, though even the authors are at pains to state that their list is based upon resale value, rather than the pleasing effect upon one's taste buds.
 Specialities of Regions
Coonawarra: Cabernet Sauvignon, Shiraz
King Valley, Vic: A range of 'offbeat' grape varieties such as Petit Manseng, Arneis, Barbera, Sangiovese etc.
Margaret River, WA: Everything!
Mornington Peninsula, Vic: Pinot Noir
Rutherglen, Vic: fortified wines e.g. ports, liqueurs and sherries
Yarra Valley: Pinot Noir, Sparkling Wines
 Further Reading
The main annual wine companions specific to Australia are written by James Halliday and Jeremy Oliver. Melbourne's newspaper, The Age, publishes wine articles and recommended buys in its Tuesday supplement section, called Epicure. Also the Sunday Age contains a regular wine lesson in the colour supplement.