Importance of Amplifier versus Preamp?

Both very important preamp more so.

The better highly efficient Class D amps out there today, and some are quite good, can deliver 500w/ch or more for comparable cost to lower power Traditional less efficient Class A/B or certainly class A amps, tube or SS.

So you can get efficiencies in speaker, amp or both these days.

Bottom line is you have to get things matched well to keep costs under control. I'd get speaker/room interactions right first using a suitable amp for the speakers, in order to be in a position first to access source sound quality meaningfully, and then tweak the pre-amp and source from there. How can one assess the sound quality of a pre-amp without the stuff downstream needed to make the music in place properly first?

There are some pretty good responses here on this subject. Sometimes we all forget that this can be pretty daunting and more so for beginners in the hobby. I guess that is true for most everything that has a "high end". Watches, cars, audio equipment, etc. You really have to know what you are doing to play and many people get so frustrated by some sales people (trying to get them to buy the most expensive items, or trying to clear out items without listening to what the buyer is all about), or "experts" that tell them to go for the very best, when they may not be there yet in terms of budget, or listening and appreciation levels.

But, I do appreciate the responses and the fact that people here generally won't look down on beginner's or snub their noses at them.

enjoy

If you are a beginner, tell ups how much you have to spend, what kind of music you listen to and what
your sonic priorities are and we can get more specific. Today there are many very good integrated amps (amp and preamp in one box) which will insure a good electrical match and save you the cost of an interconnect, if $$ is a factor. Also say new or used,

"01-26-15: Mapman
Yes, getting an integrated means an expert matches amp and pre-amp for you."

Not all experts are created equal. lol.