I cross over the subs in the Denon @ 40Hz. The CDMs go down to ~38, so I thought 40Hz would be a good choice. I have experimented with higher crossovers, but don't have a real preference. At one point I ran Audyssey and told it that I only had two main speakers and was shocked at how great the bass was from the 9NTs (without the subs). I was still missing the deep lows, so I eventually did run it again and tell it I have subs. That is where I am now: 2.2 on Audyssey Preset 1 @40Hz. Preset 2 is for my 7.2.4 setup.
I have my eye on the Anthem STR integrated amp. It has ARC and supports bass management. I figured I would use the HT bypass for the main speakers and then do a bunch of Y splitting for my subs. I assume the Anthem would integrate the subs similar to the way the Denon does, and I would not blow up my subs by having them connected to both amps. I would just turn off the Denon when I'm running two-channel (and vice versa). The good thing about the Futuras is that they go down to 25Hz so I would not even need the subs in that configuration.
Given that, I still wonder if I should shoot for the higher-end speakers. Would the Anthem drive them appropriately (Stereo integrated amplifier with 200W/400W/550W into 8/4/2 ohms)?
I need to make a decision today. The Nova II's are on order and I need to tell the store if I am going to cancel the order. The guy with the Futuras will not have them forever. I'm assuming they will be snatched up soon.