Another wattage question.

That is fine as long as you are reasonable with the volume.

Jzzmn88,

Kchahoc's answer is correct but that is one aspect.

Another aspect is how much power do you really need for the N805S??
The tech. spec says 88dB @ 1W measured 1m away.
So, if you are sitting 2m (6.6ft away), the SPL at your ears is really 82dB using 1Watt.
So, you'll get 92dB SPL @ 2m with 10W.
you'll get 102dB SPL @ 2m with 100W.
you'll get 103.6dB SPL @ 2m with 120W.
Given that we all have atleast 2 speakers in the room working at the same time, actual SPL = 106.6dB @ 2m @ 120W.

By this time the little midrange driver would have compressed!
So, really, you are just fine with a 100W amp.
But......but.....what is *more* important is what is the *current* delivery of this 100W amp???
If it is poor/mediocre, the N805S will not shine as a speaker in your room.
What is really needed is a 100W (or a 120W) amp with very high current delivery. That's what you are missing!
I was a B&W owner at one, so I know this issue with their speakers.
If you get one of those Parasound that have modest wattage but very high current delivery, you'll solve your problem w/o needing to get a higher wattage amp. You still could but it isn't necessary - you need gobs of current.
FWIW. IMHO.

As per Bombay, above. Note, however, that you need the "energy" producing capabilities in an amp in order to enjoy the dynamic headroom in music. In Bombaywalla's example above, the amp will be able to give you ~20db of headroom (difference b/ween the lowest amplitude and the highest, in the same piece of music, without changing the volume) without clipping. Say, when a full orchestra suddenly enters the scene after a quiet cadenza...