Middle Head is a large area of former heathland, partly inhabited by the Army (now hopefully giving way to the Sydney Harbour National Park, if the mean-minded federal government doesn't sell it off), and suburban sprawl. It also includes Taronga Zoo, and many neat little bays and headlands -- navigation around the streets in the area is a nightmare, as the shortest distance between two places is never a straight line, and the roads all seem to go the other way in any case..
But it's a nice place to get lost in.