As of January 2015, there are six banks in Mareeba, all located on the main street.  These banks are:

• NAB
• ANZ
• Bendigo Community Bank
• Suncorp
• WestPak
• Commonwealth Bank

If you're looking for a bank to use while on working holiday/work & holiday, SunCorp is a good choice.  They offer a Super account, so that all the superannuation various employers pay will go into the same place, making it easier to get the money out when you leave the country.  They don't charge fees for having an account, as many other banks in Australia will do.  They even offer a free "external transfer password" which will allow you to transfer your money out of the country without paying a fee for the transfer.  Their ATM cards are compatible with Bendigo Community Bank (no fee for use). They offer a telephone and computer in-branch so you can do telephone and internet banking on site.  The tellers are super friendly and try to be very helpful.  HOWEVER the tellers don't really know much about anything beyond basic transactions, they have to call the bank themselves to find out.  This may just be a small-town thing.

NAB was a runner-up; their fee structure seemed ok and their customer service was good.

Bendigo Community Bank is the "community bank" in Mareeba, which mostly seems to mean that it's a bank available in smaller communities.  They DO charge fees, and rather than offering a straight-up monthly fee, they have a structure that nickles-and-dimes, with a $5 monthly rebate.  So there's no telling what their fees are.  Might be fine, though.

WestPak is another bank commonly used by backpackers; they advertise to backpackers more.