When I asked how much power the M80s need, Debbie gave the usual "any 100wamp will do" answer. Tom didn't miss a beat... "A kilowatt."
It took a bit of browbeating by Debbie to get Tom to admit you could drive the M80s with a 100w amp, but he really believes you need a lot more power to get the best out of them. The exchange was quite entertaining.
Well they are both right, aren't they. Much depends on how far away you, type of music, and how loud you want to listen.
Disregarding other factors influencing amp performance, going back to that useful Allegro power calculator if you want 6db of headroom for dynamic range for the M80s in room and sit at no more than 2.8 metres you are good to go with 100w. You sit any further away, more watts please. http://allegro-sound.com/Power.html