US dollars are taken in most places, and take 2s, 5s, 10s and 20s, as you could get change in local currency .
Dollars are good but try to take small denominations most shops dont like to change 50 or 100 dollar bills for two beers.
US dollars. go to this site to see best rates http://travelmoney.moneysavingexpert.com/#results. Also view the site for advice on best Debit and credit cards to use abroad. I use Nationwide. Nationwide Debit Card Quick Stats. European Load: 0%. Worldwide Load: 0%. Cash withdrawal fee: None. Interest charged on cash withdrawals even if paid off in full: N/A. Cash withdrawal interest: None unless overdrawn when its 12.9%. I opened an account and put money in it just for use outside the UK. I advise my friends to use another account for abroad so that your main account is safe from cloning of cards and fraud which often happens abroad. I applied online and the whole process took 10 days to have cards etc. in hand. Have a lovely cruise