I think that speaker is by far the most important. After that it becomes a lot more difficult to say...but I think speaker cable is next, followed by amplifier, then CD player, preamp, then interconnects. And as Duke points out, any or all combinations need to work together (to achieve the sound YOU are after, which is what i assume Schipo is getting at).
I have ignored room treatments here and assumed that the room is basically ok to begin with and would be acoustically treated as a matter of course, just as it would have floor caverings, lighting, etc...as this needs to be done no matter what components you have.