Is powerfull Amps only for low sensitivity speakes?

Are powerful amps only for low sensitivity speakers? No.

My 4-way hybrid-horn/dipole system is powered by eight identical Class D amplifiers. Each amp is rated 175W RMS, 325W peak power into 8 Ohms.

The compression driver mid horns and tweeters are very sensitive, about 110 dB/W/meter.

The four 15" woofers in four U-frames are each about 95 dB/W/M.

I don't know the overall system sensitivity - the horns had to be padded down by the active crossover to match the woofers - but it's pretty high. Total power is 1,400 W RMS/ 2,600 W, peak power.

I never push SPLs very high, I want to preserve what's left of my hearing, so usually power is under 1 watt, with brief peaks of 10, or 15 watts, maybe. Lots of head room. Sounds very good.

My 1.5 W/channel Type 45 SET amp, on the other hand, also sounds very good powering sensitive horns. And that little amp has pretty much no headroom.

It's just a hunch but I would be surprised if 60W RMS pumped into 100db sensitivity sepakers doesn't at some point on bass heavy material run toward clipping. This is pretty much what I run and given my fondness of dynamic range and dislike of amp clipping I really wouldn't go below 60W.
For the more technically minded members here, given a 22' by 16.5' with 8'9" ceiling, well trapped room does 60 watts ever clip? I play it pretty loud but do the peaks require the full amp?

Dear Friends, thank you again for your comments.
May I ask your comments also for the difference between single ended triode amps and push pull tube amps in terms of 2nd and 3rd harmonics capabilities.
regards,
ozan

Power is relative.  My wife has a Mini Audio system. Cheap,Cheap!  For what it is a $300.00 complete 10 CD changer, Radio, and 6" small bookshelf speakers.  It is rated at 100W RMS/ channel. the unit will get very loud, however it has no balls.  I have a 50W RMS / channel Crown PL-1 (22,000mf reserve capacitance) and in comparison at the same volume level the difference in the dynamics is astounding.  Playing on speakers of 89db /w 1W efficiency and driving about 20W the punch and low end off of the Crown amp is like night and day compared to a double the power rated amp in the cheap system.  It is like comparing a 50W crown to a 50W Mark Levenson amp.  Even though both are rated the same wattage the Levenson power supply would have I am guessing triple reserve in the power supply.  Not to mention the quality of the components from front to end.  So we can talk about watts but that also does not tell how it sounds. Generally you get what you pay for but I always recommend listening side by side on the same equipment.  The lesser wattage amp might sound better depending on what you like.  That is what matters - what you like. 

Someone wrote:
"These statements are not accurate. If the amp makes too much power and the speaker has no need for it, the amp will be operating in a lower power region. With most higher power amps, this means it will have increased distortion. You can see this in their specs. The increased distortion is audible as brightness in most cases and will result in less detail as the distortion will mask lower level signals."

Not True! I wont even start here. I will ask you to think about percentages and hwo the FTC requires amps to be measured.