Looking for the Best Airline Miles Card!

• Continental: 20,000 miles with first purchase, plus 5,000 miles for signing up a second card user; $85 annual fee.

• Delta: 20,000 miles with first Gold SkyMiles purchase, 2,500 miles apiece for registering up to two more users; $95 annual fee waived for the first year.

• JetBlue: 50 TrueBlue points with first purchase (that's halfway to a free flight), plus a $50 credit with a JetBlue ticket purchase; $40 annual fee.

• Southwest: Eight credits with first purchase, eight more with a balance transfer (16 will get you a free flight), and a $20 account credit when you buy a flight; $59 annual fee.

• United: 30,000 miles with first Mileage Plus purchase of at least $250; $60 annual fee.