Most duty free places will give you at LEAST a 10% discount to aircrew who show/hold/wear a valid ASIC card. ... at least in oz and NZ, anyway.
personally, I would stay clear of travellex, and shop around to change your money.
IF going to NZ, just change your $$$$ at the bank or money changing place in town... they don't charge commission, and give a much better rate than travellex.
Many hotels will do an "industry" rate, although WOTIF dot com seem to do deals just as good, if not better.
most rental car companies also do deals for airline personnel as well.
some luggage companies, I am thinking of the one on Botany rd at mascot, will do you a discount..... and I believe that western Plains Zoo is sponsored by QF, and will give QF persons a discount.