I have made some small progress with my living room. Here's a photo taken today. The room looks more open, even with the remaining clutter.
The Mac 501 boxes have been put away and the B&Ks have been placed in their boxes; that's them on the floor around the coffee table. I now have my coffee table back
and don't have to contend with boxes blocking sound from the speakers. Or feeling closed in. The 501 boxes are easily 2x the size of the B&K boxes.
I am using the Furman Elite-15PF1 to support my Tripplite LCR2400, and am pleased. But the LCR now looks rather inelegant with its rack-mount faceplate. I may yet replace it with something else, perhaps a Furman SPR-20i. I missed a chance to get one at a significant discount, but may still do it later using my AMEX rewards points to bring the cost down; I don't do it now because I used half of them up on Amazon, and the remaining points would be good for only $275 off. The Panamax MAX 7500 is a little busy to my eyes, and it's more money than the Furman. Of course, a purchase like this isn't truly necessary, so I can take my time and consider carefully.