Hi,

I personnally find Virgin Atlantic FC to be good. You earn full miles and tier points on virtually all fares ( apart from the super mega cheap ones) and you can earn miles on several European carriers such as bmi british, midland, SAS, Austrian airlines.
Where in the US would you be flying to/from as VS has a relatively limited number of US gateways.
VS also teams up with Amex and the (BAA worldcard visa and the Virgin Mastercard-for UK residents only i think).

Hope this helps

Regards

TBS