Interesting thread. I'd love to emigrate to Oz but it's actually the presence of our son that's made me want to go even more, I'd like to earn enough to help him on his way and even retire early – I really can;t see that opportunity happening in the UK unless I work to the extent that I don't see him much in the week. Even my missus has asked what we do when it's lashing it down in winter – he goes mad when house boudn all day (and I can fully sympathise)
I think the decision to move is definitely made easier when your parents know why you're going and what you're doing it for. I've had a friend over there for 12 years and I've probably spoken to him/seen him more over the years than I have with a mate just 25 minutes down the road from me. I also take the view that you can spend as long trying to get from one end of the UK to the other as you do on a flight from down under.
As for the culture/history thing I'm of the view that it may not have the history that is present in the UK but when you look at the natural history and the indigenous history than there's plenty of interest.
Anyway – I'll stop rambling, should do some work!