If you don't want to carry a regular credit card, prepaid credit cards are a fantastic substitute with most of the advantages and few of the disadvantages of everyday cards.
When mass travel came into vogue in the 1960s and 70s, we had few choices about carrying money: we could use travelers checks (or travellers cheques, if you're British), receive wire transfers as we traveled, carry credit cards (yes, they did exist) to purchase things or withdraw money at a bank (after standing in line for hours), or take along huge wads of cash stuffed in our travel money belt.
Things have never been so easy.
There's nothing simpler. You pay up front. When the card runs out, you refill it. Use it like a credit card, but get no bill at the end of the month, only a statement showing what you've spent. That's why it's prepaid.
There are clear advantages
And a few disadvantages
Of course you can also use a regular credit card, your own or a new one you get just for travel.
What you can no longer afford to do is travel without a card of some sort, credit, debit or prepaid.
Credit cards - prepaid or regular - are accepted in most major cities, although they're not used as widely in developing countries. Hotels and major restaurants accept them, as do airlines and expensive shops. Smaller shops, however, often take only cash. And, in many countries there is a commission added to the credit card purchase so you'll have to pay a few percentage points above the actual listed price.
The most widely accepted cards are Visa and Mastercard, both of which have prepaid and gift versions.
Many also come with insurance, so if what you buy is stolen, lost or broken, you'll get a refund. Some credit cards also cover life insurance, health insurance or accidents.
In addition to gift cards and prepaid credit cards, there is always the virtual credit card, or VCC. This costs significantly more in fees but can also be an option depending on which country you're from. For example, in Switzerland you can get a Swiss Bankers card at tobacco shops and post offices. In the UK there's Entropay and others as well.
And then there's PayPal, if all your transactions are done online, although this is not recommended as your primary cash stash overseas.
Finally, if someone should want to give you a present before you leave (these are always welcome!) ask for one of the prepaid gift cards. Having a widely accepted form of currency is a convenience every traveler should have.