At one time, I had in place a Lexicon surround sound processor and 7.1 channel surround utilizing Kef 105s in the front, Paradigm 5se for the side, Paradigm 3se for the rear and an Axiom sub-centre combo for centre (a huge beast).
I ditched it all (heh, put to other use) for a a set up with just the Kefs in the front and the tv as centre dialogue channel. Reason? my music, which is half of my pleasure was coloured (yes I could bypass when I remembered to) but also the sound stage for films seemed distorted on occasion, as if the processor was unsure where to deliver what, where.
Now I do not fault Lexicon, hell, they almost invented surround technology, I blame the source (the discs).
Where am I going with this? Simply stating that purchasing high quality front end speakers is more important than worrying about 5.1 or 7.1 systems. If you have a high quality set of front end speakers and establish your seating arrangement appropriately, you will have an incredible soundstage that will surpass ANY mid-fi surround system.
"More" speakers does not equal "better" sound.
Just my thoughts.