I just started using the Costco Citi card. That 4% back on gas and 3% on travel and dining adds up quick for us.. I also use my Visa card through my credit union. We accumulate "score card rewards" points that can be redeemed for a variety of things, including travel. For example, we have a cruise booked on Navigator for 9 nights to the Southern Caribbean and using our points, we got a spacious balcony room for a whopping grand total of $17.55 for two people. Not a bad deal!