I started with 6.1, using a small Polk center for the rear. Then I switched to Polk FX300I's for the rear channels. I kept my opinion to myself and let guests who'd heard it both ways make their own judgments. Nearly everyone commented on how much more open home theater sounded in 7.1. As for music, I now always first introduce a new listener to the Brothers in Arms SACD. I get the same response. They'd say it sounds more airy and open now. I'm running the rears in dipole mode. They're sitting on short homemade stands in a bow window, nearly all the way back to the pleated shades. That's about 15" back from the inside wall and about 4 1/2 to 5 feet from the listening position. The front mains are 11 feet away.
My surrounds and rears are all sitting on temporary box stands made of 3/4" pine. I'm playing with the height, cutting them down a little at a time. They're carpeted with the same carpet as the floor. Okay, it might seem a little hokey looking. But there's no denying how it sounds. And with no missus to badger me about my grand experiment I'll keep playing with it until I get it right. Why not mount the surrounds on the wall? The drywall resonated. Sounded horrible. I want concrete walls, floors and ceilings. Hmm...a jail cell?

As for the 6.1 phenomenon, I never heard it. I liked 6.1 over 5.1 for movies. The experience of something coming from behind and going over your head to the front was very cool. If I had to choose between 5.1 or 7.1 for music it would depend on the material.

I don't believe 7.1 or 6.1 is absolutely necessary. But now that I'm there I won't go back.