I guess if you can't control yourself, cash and debit cards are the way to go. But if you can control yourself, credit cards with rebate dollars/cash back are the way to go.
I've gotten about $4500 back from cards that give you rebates on car purchases, since I don't plan on buying a new car anything soon, I switched to the dividend cards. I've gotten about $700 back (cash) from those this year alone. One thing you have to be wary about is they usually have $300 limits. I basically have the Citibank Dividend, AT&T Universal and Discover Card's.
I still wonder why people still pay with cash, check, debit cards at Gas Stations and Supermarkets. Someone who is paying $2.40 a gallon, I am paying $2.28 just from the rebate alone. Someone pays $100 at a supermarket, I pay $95. All I'm doing is using a credit card.
But if you DON'T pay it off each month, its not worth it