$55k per year =$42640 in your hand
$70k per year =$52300 in your hand
$100k per year =$69450 in you hand
Current top increment about $129k =$84820 in your hand (as of mid Jan 07)
These tax rates include medicare levy which is free(ish) care in the public health system, most people take out private health cover as well which adds between $1-2k per year as the publis isn't great.
http://calculators.ato.gov.au/script...lc/Summary.asp explains it all.
On top of this salary you could add $1-2K for public holidays (depending on how many you work) and probably anywhere between 0-15K for overtime depending on how much you like being at work and where you are.
Once rated (validated) your salary will increase to whatever you and ASA have negotiated your pay level will be. Somewhere between $77397 (level 2) to $118395 (Level 10 Cat D tower), $122558 (Level 11 Cat C Tower), $129736 (Level 13 Cat B Tower), all stop here, including en route. If at Sydney, continues to $139723.
You won't be rich but you will be comfortable on these salaries in most parts of Australia and can live very well.