I still recommend the Starwood American Express as the best mileage earning credit card, but some folks still insist pigheadedly that they want a United Mileageplus Visa. For those folks, I include a link to the best bonus offer going on that card: 10,000 miles with first purchase, $25 discount coupon (virtually worthless, since it can’t be used on internet purchases), and a 1,000 mile upgrade coupon (good only on full fare unless you have flown more than 25,000 with the airline and have status).
