Ok this will be a good thread.

Mains! Without getting this right your missing so much of the sound and emotion.

although Twl's demo is very convincing, I find speakers made the most dramatic change. Also, although not a component, I find the ultimate source, the CD (or LP) make a huge differance. Some CD's I use only in my car/garage/kitchen. Next, probably cables in importance. Swapping out the front end, although certainly noticable, was less dramatic. Balance and synergy is clearly the key. Budget is almost always a factor for most of us, spend your money where it will do the most good.

The most important feature in the listening experience is and always has been the imagination! No music will ever sound as good as a concert or the event in the studio. The desire to be lied to has more to do with enjoyment than even the source, although I would count that as #2.
Speakers and other componants are so far down the list they are barely worthy of mention!

I feel that speakers are definitely can most dramaticaly impact a system. I also have a variation of this question- What is more important the amp or pre-amp?

The order of importance in the audio chain goes the same as the path of the signal.