Is there an easy way to compare all of the available shopping portals across the different frequent flyer programs? I'm getting ready to pick up a new iMac when they come out and I'm interested in earning the most miles (obviously). The best deal I've seen is 2 miles per dollar at ShopOnePass (too bad I just cancelled my Continental card in order to get approved on the BA 100k or it would have been 4..). I'm just hoping to find an easy way to find the top earning program. Thanks!