G'Day mate (and all those those other stereotypical Australianisms)! :wink:
Firstly, $600,000 Australian dollars at current exchange rates is approx $417,121 USD or 230,123 British pounds. Which translates to 342,492 Euro, in case you're wondering. Um, that makes $659,794 New Zealand dollars.
Enough with the sums! For a house you're probably better off in Melb. Sydney is really very nice, but it's very crowded. If you move there expect very, very, very, very,
very narrow streets (Sydney drivers are crazy!).
In Melbourne it is my personal opinion that the Eastern suburbs are nicer, you have your choice of bayside, general suburban, or mountains (note: in Australia
mountains can mean something different than in other continents. Think very pretty but very worn down hills. It is probably the oldest country in the world after all!)
As for commute, I'm a public transport buff, so I can't tell you drive times. But stations here are comparitively safe, well equipped, and clean and very rarely have major problems (unlike Sydney lately). From city centre to the farthest reaches of the Dandenong mountain ranges is probably a couple of hours by train. Oh, and we have trams! You know, like San Francisco in the States!
All up, Sydney is probably a more fast paced sort of city. Melbourne is the older of the two and in my opinion has more personality, lovely Victorian architecture (the Queen, not the state). We love our cafes and restaurants (I'm a big fan of sushi myself) and were big on culture and art. If, however, you want night clubs and frequent influxes of hollywood movie stars, go to Sydney. They're both good choices!