I've had my ART Arrays for about two years now and must say they do a solid 40Hz. I've tried both crossovers and prefer the simpler one as well (built a single crossover with parts for both on it so it was easy to change back and forth). There is a link somewhere here on the forum to the more sophisticated crossover network if you're interested. They would make excellent L/R mains if you've got the room. If you're wanting that HT low end punch though, you're going to have to run a pair of good subs IMO. The Arrays are just not going to do that viceral slam that makes watching movies so great. I think you could probably "split" a single array in half to make a decent center channel. And Wayne's idea for the rear monitors and/or side monitors would work well.
Good luck if you go this direction and keep us up to date.