Most Important?

Once you reach a certain point, the room matters a great deal. I do not switch gear very often, but have moved several times in the last decade. In each room, the system sounded very different. Consider the difference the venue makes at a concert.

Regardless of the numbers, as long as my speakers weren't so poor that they were toxic to the music, I would spend all I could on the source *and plan for downstream upgrades later*.

I think that's the point in the source-first/speakers-first argument: it has to do with how to plan for upgrades, not with how a system is best balanced. Heck, give me great speakers now and I won't say no. However IME it is much more fun to listen to a great source through ordinary speakers than the other way around.

Since upgrading is so expensive, it makes sense to me to spend on the source of my dreams and listen to it initially through speakers that are enjoyable but somewhat less refined. Soon as the cash is available, it's speaker upgrade time.

I would personally argue that speakers are the most important (if you don't like your speakers, you won't like anything you are hearing), followed very closely by analog source. After that, amplification, then digital source. Everything else, though not unimportant, is much less important than these major components. So to the original poster's question, I would say the amp needs to be more carefully chosen than the CD player, particularly if there are other sources, especially vinyl, involved.

You need to balance everything. If the plan is to upgrade, then have an end plan for where you want to be.

My initial reaction was "get the best speakers that you can" but i think that I may have changed my mind.

I don't think that anyone has mentioned it, speakers are extremely important, but at a certain point, they start making inferior upstream components sound worse, much worse, so a "better" speaker with bad sources will sound worse.

In my personal experience, I can take my main speakers out of the system ($20,000 speakers) and put in a pair of speakers that I rebuilt and have about $700 in and the system still sounds wonderful. These speakers were about $2000 or so in the 1980's and are not typical "$700" speakers, but certainly a fraction of the price of the mains. But if I keep the mains in and take out the sources and replace with cheaper gear, it starts to sound bad in a hurry.

That being said, balance is very important. Going back to the initial question, try to have a certain level in mind and shoot for that with the whole system. If you need to continually upgrade to be at the end point, buy on Audiogon so that a good portion of the depreciation is already accounted for.

This is how I look at it.

Speakers
Amp
Preamp
Digital Source
Cables
If you want great sound....there's really a fine line between them....but speakers first.