I personally use only cash rebate cards that have no annual fee.
I cannot imagine paying for a credit card simply to receive frequent flier miles in a particular program. Perhaps other FlyerTalkers have benefitted from those credit cards more than they would from a no-annual-fee cash-back credit card, but I already earn plenty of miles. I would rather have more cash to use as I please.
Some credit cards offer cash back at the end of each year. Some rebate the money back into your account at the end of each billing cycle, reducing your credit card payment each month. Some credit cards offer a 5% rebate on gasoline; other credit cards offer up to 2% cash rebate on other items.
Go to any credit card Internet web site — Visa, MasterCard, American Express or Discover — and you can search for the fee-free cash rebate credit card that best matches your needs.
The bottom line for me is that I would rather have the money in the bank earning interest than mile or points (which can be difficult to redeem in many cases) sitting in a frequent flier account.