Given the rated power-handling capabilities of the speakers, I think either will perform to output levels you will find uncomfortable in a normal home. The M80 will handle up to 400 watts and the M60 will handle up to 250 watts.
I'm using the Denon AVR-3803, which is rated at 110-watts per channel. I'm in a large space (6000 cubic feet with two unclosable entryways to another 4500 cubic feet -- not counting a foyer and stairwell open to the second floor). I normally listen to music at -10 to -5 (on a scale from -80 to +12). I can exceed 100 dB, which I find uncomfortably loud, at +6 on the volume control. Assuming the volume control is evenly calibrated, that means I'm using approximately 27 watts of the receiver's power (each 3 dB increase requires a doubling of power). The output difference between an accurately rated 85-watt receiver and 110-watt receiver is negligible (less than 1 dB).
The bottom line is that I think you will be very happy with the M60s given your receiver choice and your listening preferences.
