i have carried cash, credit cards and traveller cheques with me. My parents bought a place in florida near frost proof and locals would get tired of me using traveller cheques all the time as it would empty there tills so i stopped bringing them but everywhere in the parks and tourist areas takes them no problem though so if thats the only area your are in they are useful. I dont spend enough time there to warrant having a bank account near the place in florida just to store money/set up a atm card or get credit card or at my bank as they charge fees for everything so only thing left for me is cash and credit cards even though sometimes i spend a month to 3 months in florida a year. I normally just toss a grand or two on my credit card through online banking and bring a wad of cash and im good for a month or two in florida, good to have alternatives though as ive had my credit card locked while in florida for suspisious spending i guess in a different country and didnt bring enough cash one year..not thats its a big deal got card unlocked after a 5 minute phone call but some people do over react to small bumps while travelling.
I tried the pre-paid cc they work some places and some they dont problem with them is they arnt registered to a address or anything on most of them so its ymmv on where they will work, if you want to use them online they wont work 95%+ of the time either because of the registration issue it doesnt match up with shipping address so it will deny order. They have a issue that i dont like just like travellers cheques and both have fees to buy....
I used to use travellers cheques first, cash second then resort to cc for big purchases as i didnt walk around with lots of money everyday I would bring a set limit of what i wanted to spend daily and always was under it unless a emergency happened and thats what backup cc was for.