I think staying away from the outback is a wise decision - it's really way more full-on than most people think; Gwenith's posted on that before in this forum, so I don't really need to say any more!
The east coast is (relatively) more densely populated - it comprises Queensland (capital Brisbane, also the Gold Coast), New South Wales (capital Sydney, also Newcastle), the ACT (Canberra), Victoria (Melbourne, also Geelong) and Tasmania (Hobart, also Launceston). There are more kinds of employment choices (eg hospitals), and it's relatively quick to travel interstate - flights from Melbourne to Sydney take about an hour, for example.
The west coast primarily comprises Western Australia (Perth, also Geraldton) - the weather is generally more tropical, and the people are a bit more laid back. It's a long way from everywhere else, so if you're interested in sight-seeing it's harder to be based in, but it has some spectacular scenery.
The Top End includes the Northern Territory (Darwin, also Katherine) and the northern part of WA (Broome, the Kimberly) and north-western Queensland.
South Australia (Adelaide) is kind of a compromise between east and west - the laidback, less urban qualitites of WA, but closer to the sights of the east coast.
For a bit of an overview check out the Lonely Planet entry: http://www.lonelyplanet.com/worldgui...ific/australia