http://finance.yahoo.com/news/4-reasons-to-use-credit-cards-versus-debit-cards.html
My wife and I don't even have a debit card. Everything possible goes on our Costco Executive Membership AMEX credit cards, which pays anything from 1% to 4% cash back bonus (last year we got a refund check for over $1,000) as well as special bonuses on some expenditures (for example, I get 5% back for any charges at a Marriott property, which I usually stay at when I travel on business). And on top of that, COSTCO gives you store credit based on the money you actually spend in their stores (last year that came to over $140 in store credit).
And, we have never paid a single dime of interest in the 3+ years that we've had this account and there are NO annual fees either.

OCU