I bought a Blu-ray player that was on special about $40 cheaper than other stores from HN and also took advantage of the 2x$20 iTunes for $20 promo last month. However when I paid for it all I accidentally used the wrong amex, the promo I had registered to my other Amex card, doh
(I still got two great deals, Just missed out on the equivalent of getting $40 iTunes for nothing at all!)