+1 for the great ocean road. Do that in the day time though. It might have changed since I was there last, but a few locals treat that as a racetrack, and know it 'too well' at night. A couple of times on a bike I've gone through there and was almost collected at night.

Further westward (or perhaps northwest is more accurate) - most people I know that went through coober pedy said it was one of those must do things. I'm the kind of person who find themselves more likely to want to have a crossbred mutt from the lost dogs home, than a purebred this or that, and in a strange way, it's how I feel about outback South Australia in general - it might not have the beauty (in some people's eyes) of a rainforest, but there's something very calming about places that look a little desolate.