The Bank of America Hawaiian Airlines Visa gives you 2 miles for each dollar spent on the purchase of Hawaiian Airlines tickets. I use it for everything when I'm in Hawaii and from time to time, I get surprised by additional bonus miles from purchasing from various businesses in the islands.

Hawaiian Airmiles is also one of the few remaining airlines (at least that I'm aware of) that you can transfer points into (from Amex and Diners) and then transfer on to other programs without terrible exchange ratios. (E.g., 1000 Amex points = 1300 Hilton Honors. 1000 Amex points = 1000 Hawaiian miles = 2000 Hilton Honors points.)