I used Chase SouthWest card which gives you 50000 points (when i got it , it was worth $833, now its worth 714) for spending 2000$ in first 3 months. This is far better than any 100-200$ cash back bonus on cards. Only drawback is SouthWest is not as cheap as it used to be and they dont fly from everywhere to everywhere like american/delta. Just considering rewards, any chase card is good, never had amex and discover comes in second as far as i know. Credit cards from BOA and wells Fargo sucks in reward program.