Which card to use overseas

[SuperDan]

Hello,
I am planning an overseas trip to USA and Europe. I have a Mastercard linked to a European bank account, which runs in Euro, and I have an ANZ Gold Visa card.
I am just wondering whats the best thing to do at the moment.
Buy some dollar and Euro at the anz branch (supposed to be commission free)? Use a credit card in the Usa ( which one), what to do in Europe?
Any advice?
Thanks

[Bozeman]

We keep a CapitalOne Visa card (using my parents' address in the US) for use outside New Zealand and for internet shopping. No annual fee and no foreign transaction charges. Their customer service is terrible but there is usually no need to interact.

[SuperDan]

We keep a CapitalOne Visa card (using my parents' address in the US) for use outside New Zealand and for internet shopping. No annual fee and no foreign transaction charges. Their customer service is terrible but there is usually no need to interact.

Thanks, but I do nor have any US cards. Just a NZ and an Austrian card