(1) Aussies have grown up with only 5 TV channels. Less than a 3rd of the population has cable. Personally I think having only 5 channels should be deemed cruel and unusual punishment and outlawed in the constitution and I've written Prime Minister what's his face to say as much. Just b/c they don't know what they're missing doesn't mean you won't. Cable ain't cheap but it's a must have so just lock it in and don't ask too many questions.
(2) You will get a speeding ticket - maybe multiple tickets. Lead footed Americans are not able to adjust to the small increments of KPH vs. MPH and with cameras at seemingly every light you can't play the dumb American to get out of it with the PoPo. The trick is to keep your US license for as long as possible so that your points go against it and then don't transfer when you finally get an Aussie license :-)
(3) 4 weeks vacation! Now that's a difference that's not only nice, it's a necessity when you're this far away from everything. The Aussies use it to travel around the parts of country where no one in their right mind would want to live, the Poms use it to head back to the UK and remind themselves why they left, and the Americans are still confused and think we're getting away with something.
So, as you can see...same, same but different. There's lots more to comment on as well. I'm just getting started. As always if there's something you're specifically interested in just say the word. I've probably got an opinion on it. I'm out.