I live in Victoria, but I'm assuming that the bank charges would be similar in Perth. I bank with the commonwealth bank and if I use a non-Commonwealth bank ATM I get charged AU$1.35. But there are heaps of Commonwealth ATMs around so it's not often that I have to, mostly in Petrol stations and Pubs. Cash out via EFTPOS is also another easy way of taking money out of your account and banks don't usually charge at all for that. Commonwealth Bank charges a flat AU$5.00 a month to their everyday (Streamline) accounts whether you make transactions or not, which is pretty excessive I think. My sister changed to the National bank because of this and she is quite happy with them. One of my best mates works at Westpac and from what she says, they treat their customers very well. But essentially, they are all out to make us much money from us as possible!! If you want a credit card, the best company is Virgin:- www.virgin.com.au
there are no annual fees (for all others, it is $30 plus) and the interest rates are low, also you get to pick the colour of the card! (mine is pink
Definately check out the other banks that Wyzfen gave links to, also credit unions and community banks (I'm not sure what the ones in Perth are, but it shouldn't be too hard to find out once you get there).
Have fun!! When do you arrive? And check out Margaret River if you like wine