Hmmm. Good question.
I've lived in UK, Holland, Italy, Thailand, Germany, Australia and spend months at a time in the US and Scandinavia.
Right now I'm in Australia. It's pretty good, better than London (and I was also lucky enough to 'afford' London). I'm in the Eastern Suburbs of Sydney, which is pretty London-like though.
I miss European culture - I resent paying $250 (about £130) for a £40 elc toy and expensive French imports. I'm sad that DD can't get on a plane and be in France/Italy/Germany any more - if we stay here it will be her gap year mega-trip.
I love the sun, friendly people (have had to learn how to smile at strangers). I could spend years travelling around Australia and the fabulous islands and still never see it all. Australia is huge, much bigger than people generally realise and has many climates. I can ski here and sunbathe in the tropics! DD can go to the beach, see dolphins, koalas, kangaroos - all sorts (not squirrels though!). Its a fantastic outdoor lifestyle. Its easy to eat healthily - no convenience foods in the supermarket (no M&S sob).
Internet is rubbish, crappy online shopping, can't find anything out online - horrors have to phone people. I've left behind my tv on demand, 2Gb internet link, Sky plus.
On the other hand I could sell my London house and buy a 4/5 bed house with pool mortgage-free. MORTGAGE FREE!!! At 35. It's the holy grail.
Out of all the places I've lived so far Australia is best. Loved Holland too.
The shopping is crap though. Fashion is terrible.
Not keen on the US any more - I don't like the fact that there's a lot of religion and holier than thou attitudes but so much hatred, racism, nepotism and that porn DVDs are the most commonly rented out of all genres. Don't like the guns or the fact that plough is spelled plow. Shudder.
Loved Italy, hated Germany, Scandinavia ok. Adored Thailand. Could definitely settle there permanently.