Good question, the trigger was sometime in 2008/9 I think me and my wife decided that we were bored of working/living in Malaysia so we decided to apply for something else and the Aussie PR was reasonably easy to get. Compared to the UK, Canada and the US, Australia was then booming in the industries I was interested in (energy) with decent weather and access to Malaysia.

But I haven't migrated (yet?) because the Aussie economy is now tanking, plus I will have to put a lot more effort into getting a higher paying job in Australia since I'm already making decent money here. I'm also a bit turned off by the kampung attitude by some Aussies but that doesn't seem to be a major issue in the major cities.

fyi, i earned rm10-15k in MY b4 coming to oz..

imo.. rm10-15k in MY is really nothing, as in the buying power is not high.. (which has been discussed many many times)

it all depends on what you want..

For me, the reason I would like to migrate is more towards the lifestyle, culture, dissatisfaction with Malaysia, and weather.  Money is definitely a factor, just not the biggest one.