Hi Paula
In our case we like a mediteranian climate, Therefore Darwin and Cairns to humid, also Sydney too expensive, Brisbane maybe a little too humid and expensive, perth too far away from the other major Oz cities, Melbourne probably as wet as scotland.
Adelaide has a mediteranian like climate and is fairly small for a capital city ( which suits us personally)but there is still lots going on.
Upon researching a little further it has a good education system, Houses are a bit cheaper than in other parts of Oz
This was our starting point.
Easter 2009 went for a holiday and it was everything we expected and more. Loved it. came back determined to make it work, and it has been very hard work at times.
That is why we chose adelaide over the othe cities but everyone is different
Alan