I personally would stay away from 100 Hz crossover. It generally (to me) has brought unhappy moments to my ears as my sub was amplifying to heavily in the audible range. I generally like my sub to do more feely stuff, but also to take over some of the work of my speakers. I have my H/K 630 crossed over at 60 Hz for the front mains and 80 Hz for all my other speakers. I've found this to be pretty much the most desirable results. Although, of course, it does vary from person to person.

"We're on the island of Misfit Toys"