Which country?
Sigh :)
There are loads of good ones in the US. Depends what you spend on.
BofA Cash Rewards is good, Amex Blue Cash Preferred is good if your grocery store accepts Amex and you spend enough there. Quicksilver (Cap One IIRC) is straight up 1.5% on everything, if you just want the one card. Barclays do a travel one that has a nice intro bonus and 2.2% effective if you use it to travel.