Need some Amp help - a little new to properly powering speakers

@willemj , I think you might be confusing sensitivity with efficiency. They are not the same; the latter is based on power and ignores impedance, the former is based on voltage and impedance thus matters quite a lot!

Now if you are driving a larger room, you will need serious power regardless. If that is the case, you might consider a set of Sound Labs, as they are better at playing the higher sound pressure levels you might need in a larger room.

Many good suggestions here, two that stand out are:

If you increase power and keep the same mass market level of product, you will hear little improvement.  Be sure to go up in quality vs. power, you will hear the difference.

You should audition a good quality tube amplifier.  Tubes have a different sound that many of us prefer.  My preference is for Conrad-Johnson products in both areas, many c-j amps are available on the used market.

Enjoy the search...

@moskaudio     

I hope all of this hasn't been too confusing.  To directly answer your question... No, you do not need more power simply because a speaker can handle that much power.  You might have seen that others quoted that you have an 8 ohm speaker that is rated at 88db sensitivity.  What that tells us is that you could get away with as little as 30 watts per channel, if the amplifier is built well enough to give you that full rich sound that you seek with higher power.  One thing that I have found is that on lower priced items, that it does require more power supply to create more power, so because of that, more powerful amplifiers can often sound better at low volumes,  but overall, If an amplifier is well designed, then you don't necessarily need much. Your Yamaha is a fine receiver, but it is not in the realm of good audiophile equipment. With that, I might recommend a good receiver like maybe an Outlaw or maybe a 50 to 100 watt integrated amp, a used Audio Refinement or Arcam would do a great job.... There are a ton of good integrateds.  If you like that Idea, you'll get plenty of suggestions.  I've heard your speakers, set up properly with good amplification they are a very satisfying sound.  I hope this helps, Tim 

How happy are you with the sound of the Polk/Rotel combo? 
If you are not yet satisfied; I'd try 'better' speakers with the Rotel, first. 
I'm talking only about 2 channel music here.
I had a Rotel RX-1052 powering old Boston Acoustic T-830 acoustic suspension speakers. That combo sounded great at low volumes. I later upgraded to Canton Ergo 1002 DC bass reflex design larger towers. They need to play quite a bit louder to get everything out of the music. Both are rated at 90 dB @ 1W @ 1M, but the Cantons actually play louder at the same volume setting.

Tim,
We have a similar assessment of moskaudio's current audio system. The speakers are pretty decent and will respond to better quality amplifiers. The Yamaha receiver is the relative weak link in this system. Evidence is that  lower level sound quality improved noticeably when the Rotel replaced the Yamaha. I do believe that moskaudio has recognized the necessity for moving toward a amplifier of "higher quality ". There’s more potential with the Polk speakers to be gained.
Charles