Chase offers a couple of cashback cards including a 5% rebate card on gas & groceries. Since most cashback card have an annual payout limit people many people might need multiple cards and getting them from different banks might be the best bet.

And of course make sure the cards are registered with Upromise to get the 1cent back from Exxon-Mobil (but there is a new limit - since June this year you need to buy a minimum of 20 Gallons of retail fuel per month to receive any money from them).

There are a bunch of cashback cards on my site @ http://www.andrewcram.com/frequentflyerCC.html