Re: @ Mike Flugennock
An added plus of using my AMEX card is that they automatically double the manufacturers warranty on almost everything you buy (with some limits). It's saved me a bundle a few times.
Also, I have a cash back card, so at the end of the year, I get almost a grand back in cash. That's money I wouldn't have if I used cash everywhere! I pay off the card every month, so I don't pay anything to use it.