If you were only going to be using m60's with a sub, and not other speakers, I would say to go with a lower crossover, since the 60's will handle the lows fine. However, if you throw HT into the loop, then things change a bit. I enjoy music and HT and use an 80hz crossover on my receiver and set all speakers to small in the setup menu. This is a great overall setting for all applications and THX recommends it also. Even at 80hz, you still get killer bass from the m60's.
my setup: m60's vp150 ep500 4 Qs8's
Denon 2805
