Airspike,

Costco does take Amex - their no fee card gives some percent of money back BUT the Hilton Amex card (also no fee) gives 3 hilton points per dollar charged (hint miles transferred from an airline only yield 2 for 1) They were recently running a special where you got 7500 points for getting and using the card once - almost enough for a stay at an opportunity level hotel.
When you fly you have to stay somewhere - right?