How many watts per channel are enough?

Hey, follow K.I.S.S. (keep it simple, stupid), the general rule of thumb is to use double the required RMS output, fuse or breaker protect the speakers, and listen for audible distortion. This setup can even be used to lower THD. If you have 8 Ohm speakers and a 4 Ohm amp you can cut THD in half while maintaining proper power output. I, for instance, use 12 ohm speakers L/C/R/SR/SL on a 8 ohm amp. This technique works wonders for sound quality while maintaining volume levels.

Zd 452, I agree with you. When I bought my speakers last year the guy was running a 40 watt tube amp on them. I could not believe 40 watts would power these speakers. They are a difficult load at 85db sensitivity. When I got them home my 100 watt tube amp almost ran out of steam at high levels. All watts are not created the same.

Agree w/Zd524...I had two 25W amps (one tube and one SS), and the tube amp hit a brick wall REAL quick, while the SS seemingly never got tired. It's more about impedance swings and phase angle, not sensitivity.

I have to agree with Zd542, the wattage ratings have not been very consistent in my experience. However, I think you should be ok unless you want to play really loud. Is there a way you could audition the amps before buying?

Based on your listening levels, that's plenty. Even in a relatively large room, such as yours, you'll be fine. Especially given the speakers relatively benign load on the amps.