We spent 4 days in Cairns, which is the main 'Great Barrier Reef' city. We went snorkeling for a full day, relaxed on the beach, and kayaked at Palm Beach.
Lookout over Brisbane
There's nothing quite like Australian coffee at the beach.
View from our hotel/apartment in Miami Beach (Gold Coast). You can see Surfer's Paradise in the background.
Sydney!
Darling Harbour in Sydney
We went to a Wildlife Park in Sydney and saw all the cool native animals (and played with butterflies, mostly).
There was an event called 'Vivid' going on in Sydney while we were there. Artwork was displayed all around Sydney Harbour and the Opera House had animations on it at night.