gem1981 - DH and I are Aussies, but we live in the UK (and had children here). I really miss the extended family and it is too expenisve for us to get back more than once every 2-3 years, but we are on email and webcam every other day so that helps.
We have stayed in the UK because...
1)Better quality fo life for our DCs
2)more relaxed way of life
3)fed up of being fleeced for every penny we earn in taxes by the Australia
But to be fair, we lived in Sydney and moved to a country town in UK (we may not have lasted as long in London!)
Australian's aren't all rude, but they are a lot less reserved than British, so sometimes it may come across that way
Plenty of cultural stuff - I think someone started a thread on Australian culture (artists, musicians etc) sometime back. And with something like 1 in 2 Australians being only 2nd generation, there are plenty of multicultural influences, In sydney for example, there is a big south east asian influence.
If you are living in the cities, the cost of living is very expensive. Cheaper in the country, but very remote and may be difficult for jobs. The cities do tend to be more spread out than here in UK, so if you are living in the suburbs, be prepared for a long commute. Public transport is OK, but lots of the motorways have tolls now. It would be easily a 2 hour commute from the outskirts of Sydney to the middle of the city.
TV is rubbish (free-to-air). No nice way of putting that, but it isn't a big a part of life as in UK I think.
Customer service on the whole is generally better I have found in UK.
Shopping not as good generally, but that is improving I think. Plenty of supermarkets though, and you can do online grocery shopping. Like here, they are experiencing the credit crunch so fresh food prices are expensive. When we were there in May this year, we found food relatively expensive to UK, but clothing (especially basic clothing) relatively cheap.
Country areas - sexism and racism is an issue, but not so much in the city. Certainly no more than what I have seen in the UK. You will get the p*s taken out of you because you are a Brit, but the same way that we Aussies get the p*s taken out of us in UK. Its all good fun and not to be taken seriously. Also don't forget that Australians have a habit of shortening names as an endearment - the cricket teams are known as Kiwis, Pommies, Pakies, Windies etc - but this is not a term of abuse of racism!
Hope that helps...