I use my AS Visa card to pay for the light rail.
Over the course of 20 or so roundtrips into the downtown Seattle area, I've saved $1,400 over the cost of the taxis, which paid for a FC ticket to Hawaii!
Sometimes, the light rail is even faster than the taxis used to be!
I've only picked up 200 miles for the light rail for the year, though.
@:-)