Ok this will be a good thread.

source.

I'd put the highest priority on the source. But I'd also add that Synergy between components/cables/tweaks plays a major roll in making or breaking a system. You can go out and randomly pick out a sampling of very expensive high end components that may sound like crap when combined together, whereas careful selection and pairing of some of the same components with others would yield a magical system. Speakers can potentially have the most radical effect/change on the 'sound of the system', but, as the first respondant points out; Garbage in = garbage out! Or, as I pointed out in another thread, changing the speakers may make the garbage smell sweeter, but it's still garbage!

The person(or you) behind the system.

A good, but oft repeated thread. Source

Musiqlovr, I whole heartedly agree with you, speakers should always come first. Let me explain.

I use to frequent an audio business of rare quality. It was owned by Keith Yates of home theater design fame. He carried only the very best components. I watched and listened to a parade of great speakers debut on a weekly basis. All speakers enjoyed the best upstream components available. One speaker stood clearly above and beyond all others. I had to have that speaker. Knowing what kind of amp I needed to drive that speaker culled out almost all choices. I was lucky to have a wonderful cd player demonstrated at my place. That left only the pre amp. I just chose the most sonically invisible one I could afford.

I'm in music heaven now. And that is all because I realized the fallacy of front end first. It doesn't matter what golden player you plug into a sows ear of a speaker, it still will be a sows ear. I've heard plenty of great everything but the speaker systems, and every one was a disappointment.