Do you plan on carrying a balance every month or will you be paying it off in full? If you do not want to carry a balance, I recommend an American Express card with the rewards program. If you do plan on carrying a balance from month to month, all of the major airliners have their own credit card that will earn miles in their frequent flyer program. Pick the card that will earn miles on an airline that will benefit you the most.
In my opinion the American Express card Rewards is the better deal. You can use points on many airlines as well as apply them to hotel stays, rental cars, and cruises. With most AMEX cards though, you will be required to pay the balance in full every month.
A noble spirit embiggens the smallest man...