Though I totally agree that Starwood AMEX is best - you might also consider the Hilton Honors Amex, and maybe even get both. It has NO annual fee, and I think you get a bonus of 7500 points with first purchase. Then 3 hhonors points per $, (5 if at an hhonors hotel).

Most people on FT (me included) value 1 Starpoint as worth more than 3 Hhonors points - and if you are looking for airline miles, Starwood is much better. But I figured I'd throw this out as another option.