Lampy, maybe the lowest power amp use that's been reported here with M80s is when Mojo connected the amplifier in his wife's boombox(probably about 2-3 watts realistically)to his M80s. At a moderate listening level the result wasn't audibly different from a high powered receiver.
Considering that the sound level at a typical listening distance of about 10'(both direct sound and room reflections taken into account)would be about 86dB for 1 watt with the M80s, a 2 watt amplifier would be okay for a peak level less than about 90dB.
