Designtechnica has a column on 7.1 surround sound:
As a home theater tech critic, I spend much of my time evangelizing for surround sound. I do it unashamedly and with all my heart. I love surround sound and I want everyone else to get as much pleasure from it as I do. But I worry that a lot of people still waiting to dip a toe in the sound-field are turned off by a bunch of seemingly conflicting numbers: 5.1 and 6.1 and 7.1.
I’ve seen this over and over with people who are just getting into home theater as a hobby. When told they have a choice of 5.1 or 6.1 or 7.1 channels, their eyes glaze over and they mumble something along the lines of: “Um, well, I guess I’ll just keep my two speakers and think about it.” When speaking with newbies, I’ve learned to discuss surround as a 5.1-channel medium, which it essentially is, and leave it at that.