I realize we each have our own preferences and priorities. I've also noticed Audiogon is very 2 channel focused, while sites like AVS Forum have more interest in multichannel listening, independent of whether that is a movie or music.
For those interested, below is a posting from sdurani at www.avsforum.com, which I think provides a very good explanation of 7.1 versus 5.1. This also correlates very closely with my own listening experiences of 5.1 compared to 7.1:
"7.1 set-ups have a few noticeable advantages in the surround field over 5.1 layouts: more precise directionality (4 hard points vs only 2), better envelopment (4 speakers can literally 'surround' you better than 2 speakers ever could), and greater imaging stability (no matter where you sit, sounds at your sides and sounds from behind you stay locked at those locations because there are speakers there).
It is difficult, if not impossible, to get all that from only 2 surround speakers. Doesn't matter how good they are, one pair of surrounds can't be in two places at once (at your sides and behind you simultaneously). The best and easiest way to get stable rear-vs-side imaging in the surround field is to simply place a pair of surrounds at your sides and another pair spread out behind you. Of course, this assumes you can tell when sounds are coming from your sides vs coming from behind you. If you can't, then stick to a 5.1 set-up.
To deal with a couple of myths in this thread:
Room size or space is not a determining factor for 7.1 layouts. What's more important is seating location. If you're in a large room but your seating is against the back wall, then you're a poor candidate for a 7.1 set-up (no room behind you for the rear speakers). But if you're in a small room and your couch is away from the back wall, then you could probably do a nice 7.1 set-up (where surround-back information really sounds like it's coming from behind you).
Consumer level 7.1 surround processors have been around for almost 20 years, pre-dating 5.1 soundtracks by a solid 8 years. People using those processors haven't been waiting 2 decades for material that takes advantage of the extra speakers. They've been using all 7 speakers since day one. ANY source, no matter how many channels, can take advantage of a 7.1-speaker layout. Surround information contains sounds that will image at your left side, at your right side, and behind you. By sending these specific sounds to their respective speakers (which is what PLIIx does) you get imaging stability, wrap-around envelopment and surround directionality that a 5.1 set-up cannot deliver.
Since you already have a 5.1 set-up, I would move the RS-3 surrounds directly to the sides of the primary listening spot. This will give you stable lateral imaging, which is also important when listening to music in surround. For the rear speakers, I would get a pair of RB-3 bookshelf speakers (which match the sound of your other speakers) and spread them out at least 60 degrees apart on the back wall. The separation will provide you better envelopment and allow you to hear the rears in stereo (sound over your left shoulder vs sound over your right shoulder).
Use the attached 7.1 placement diagram as a starting point for your layout."
Note- the attachment referenced above was the Dolby recommendation for 7.1 speaker placement from their web site.
Thanks
Bruce