I have my M60s and EP350 set with a crossover of around 50Hz and i use them full range for music and movies.
I don't prefer the sound of the subwoofer at higher frequencies. I find it too bassy and turning down the gain only provides weaker explosions for movies.
Whatever blend you find sounds good to you, use it.
Don't worry about the 'rule' quoters on the necessity to use only a Dolby Digital point of 80Hz, etc etc.

Do what sounds good to you, period.

"Those who preach the myths of audio are ignorant of truth."