This summer I had the opportunity to share an afternoon with several Australian planners. What I see as the major difference between the two cultures is that the Australian citizen is more comfortable with regulations. Perhaps this is due to more socialistic nature of your governmental history. In the states we often have a difficult time with citizens accepting development standards, under a percieved freedom to do anything with their own land.
In the states the local level controls subdivision of land, zoning, design standards, historic preservation, business licensing and nuisances. The state passes 'enabling legsislation' granting such authority, with usually broad parameters.
The state has jurisdiction over several environmental matters, such as hazardous wastes, major projects and water quality. Water and sewer systems usually require a state level review. Construction of major roadways is financed mostly by federal and state funds: construction proposals must be approved by the state.
The state jurisdiction is more often than not the result of federal legislation as implemented through federal agencies such as the Environmental Protection Agency.