I've lived in:
- Sydney (I was born there!)
- Wagga Wagga (a very large country town halfway-ish between Sydney and Melbourne)
- Melbourne (one of the best cities on the planet)
- a coastal town north of Sydney called Port Macquarie (great place to retire to - you'll live a longer life because nothing EVER ***** HAPPENS THERE!)
- Gold Coast (good place to party, not so great to live)
- Brisbane (where I am now, and have been for more than a decade).
I'd recommend Brisbane as THE place to live, based on experience; I find it's a good compromise between Sydney and Melbourne, with many of the benefits and a lot fewer of the downsides. You're an hour's drive away from two of the premier beach resorts of Australia, in Surfers Paradise and Noosa (close enough for a night out without having to spring for a motel). Brisbane has a pretty good year round climate, reasonable shopping and some world class restaurants and pubs (the famous Breakfast Creek Hotel for steak cannot be beaten!). There's a vibrant nightlife, Australia Zoo's up the road... excellent schools, heaps of sporting events... U2 played here last night...