Any credit card such as Visa, MasterCard can be used overseas. It is very convenient and economical.
Travel card is a kind of debit card (cash card) in foreign currency. You have to buy foreign currency & deposit in your card. It is very convenient also. Ask your bank for details, most of local banks provide travel card.
ANZ Gold MasterCard (annual fee $80) covers international travel insurance.
The Warehouse Travel Insurance: http://www.twti.co.nz/?gclid=CM-5t5GW8KgCFQXabgod0n5OBw
Banks normally charge 2.5-3% as foreign currency converting fees. The rate is reasonable & you can not save this by using any other method. I am not quite sure which bank charges less. You can find this information from the websites of banks.