From Sydney we flew into Melbourne and took a car to the Great Ocean Road, that spans a good part of the coast between Melbourne and Adelaide. We didn't have time to go all the way there but drove through the first 300kms and had a blast.
We've lived for a long time in California, near the Highway 1 which is revered for its coastline. Shortly before leaving the US we were talking about it and how it is pretty much the same for a long time. I'd have to add that it doesn't quite compare to this Great Ocean Road.
After landing late because of our first (and hopefully only) missed flight, we picked up the car and drove to Lorne, which was pretty much the beginning of the road for us.