Correct me if I'm wrong but I'd assume if they can handle more wattage then it would improve the sound of the speakers to give them more wattage.
Saying you are flat out wrong is not fair (and doesn't help any as you said), but the notion that any speaker needs X wpc to sound their best is a common misconception.
First, the speaker ratings are very conservative and indicate how much power they can reasonably take without damage. Nearly ALL speakers can take far more power than their rating for short periods of time. Driving speakers with an underpowered amp can blow the speakers (tweeters) far more easily than having alot of clean power that is in excess of the speaker's stated maximum. This is because as an amp approaches its maximum output, its distortion goes up and and if driven too hard it can clip the waveform (square off the tops). A more powerful amp can play louder before it clips and thus is safer than playing a lower powered amp full out. Of course if you were to send a 200 wpc rated speaker 500 watts of clean, undistorted power continuously, it will blow the speakers too. For a few seconds though, no problem.
Now what does all of this have to do with loudness (which is the real question)?
The loudness you hear at your listening position is dependent on many factors: power from the amp/receiver, speaker sensitivity, and room acoustics to name the most important. PLHart was trying to give you an example of how little power you really need to get to very high sound pressure levels. Highly efficient speakers (say 90 dB or greater) require very little power unless your room is gigantic. The amount of power you require to get to an acceptably loud level is the amount of power you require, period - speakers don't need a given amount of power to 'sound their best'.
I chuckle when I see people say that this speaker or that really needs 200 wpc to sound its best. Wouldn't that mean that it only sounds good when it is excruciatingly loud? That it only sounds good when the in-room SPL is 105 dB and sounds terrible at 90dB? Either of those levels will cause permanent hearing damage if sustained for too long.
Now there is value to using separate amps - not so much because you really need the excess power, but because they work less hard to get to the level you do require and will not clip the signal as well as the fact that they can better handle momentary transients that might require 10x the power to play accurately without clipping. But as PLHart pointed out, it really doesn't take much power to reach very high level SPLs.
Just as an example, I have an Onkyo TX-SR502 (75 wpc) in one of my smaller rooms (about 12'x14')with older JBL speakers (92dB sensitivity). After calibration, I get Dolby Reference level of 105dB peaks at the listening position with the volume dial set at 50. The receiver is well within its linear operating range (not clipping) and the sound is crystal clear - AND SO LOUD I CAN'T HANDLE IT FOR VERY LONG!
