I bought a yellow heavy duty 12v air pump from Pep Boys about 2 years ago. It's all metal, pretty well constructed and fills tires plenty fast (2-3 minutes from 15 psi to 32). Cost $40 and has paid for itself many times over already. The yellow one has a standard 12v cigarette power plug on it, the also have an even heavier red one that only has battery clamps on the power leads. It's made by Master Flow.

-Todd
1987 Montero 2.6l 5-speed (Sold...but I still miss her)
2008 Jeep Patriot Sport 4x4