Is there such a thing as too much power?

Answering your title question...NO!  You can never, ever,ever have too much power!!  You just have to be careful to never overcrank the volume control.  Always keep your system well fed! (quality and quantity)

OP seems to imply that an amplifier's contribution to SQ is theoretically solely based on watts and not circuit design and a bazillion other factors.

This discussion often becomes an "all-other-things-being-equal" hypothetical discussion.  If nothing else is adversely affected by increasing power, then it probably doesn't hurt to have more power in reserve. 

But, depending on how loud one listens to music, the efficiency of the speakers, and the acoustical environment, having a big reserve of power may not increase sound quality.

Also, being able to deliver a lot of power means that the amp has to be built specifically for that priority, which typically means using a lot of output devices in parallel.  There are some people who say that using multiple tubes or transistors degrades the sound--simpler is purer.

Also, some of the higher output transistors or tubes may not be the best sounding.  I have heard tube amps that can be made to run on different tube types, and I usually end up preferring the lower output tube types (assuming reasonably high efficiency speakers).

Among both tube amps and solid state amps, most of my favorites are low-powered amps.  I like the sound of the two First Watt solid state amps I've heard more I like many ultra expensive high-powered solid state amps (most sound lifeless when playing at modest volume), and I MUCH prefer low-powered tube amps to high-powered ones.  I have fairly high efficiency speakers (99 db/w), and they really sound best with either low-powered push/pull or single-ended triode amps.

+1 @larryi & @three_easy_payments

I would add a couple of things:

1) Within a given class of operation (A, AB, D), and if everything else is equal, more amplifier power tends to mean greater cost. So for a given investment in an amplifier choosing a lower powered design tends to mean that a greater percentage of that investment can go toward quality rather than toward watts.

2) Some excerpts from posts by Atmasphere in this thread (the rest of his posts in that thread are also well worth reading):

Its important with any system to avoid distortion but in fact distortion is the name of the game as the human ear translates distortion into tonality....

... A lot of push-pull amplifiers will actually make more distortion below a certain power level, so for those amplifiers its helpful to have a speaker that is a little less efficient, so the distortion is happening at a lower level and is hopefully less noticeable. But this is why some amps seem to lack detail at lower power levels.

There is definitely more to this than meets the eye!

... There is something to the idea that smaller amps sound better. In the case of push-pull tube amps, this has almost entirely to do with the output transformer itself. The reason for this is that the more power the output transformer can handle, the less bandwidth it has. So in the larger designs, usually the designer has made a tradeoff based entirely on what he thinks is important....

... Now the problem with push-pull is often that there is a phase-splitter circuit that introduces some distortion. This is not true of all P-P amps, but it is true of most of them. This generally is not an issue until you get into the lower power regions of the amplifier, at which point the distortion of the phase splitter comes into play. For this reason a highly efficient speaker (+98 db or so) may not be the best choice with a plus-100 watt amplifier as you may never get the amp out of that region of higher distortion at lower power levels.

Regards,
-- Al
 

yes, spending money that could be spent on content, other equipment, better speakers ...

a ton of SS power or some tube power, I say, get efficient speakers, get tube amp.

and, avoiding size, weight, heat, electrical use is good! optional locations if smaller/lighter/less heat!