I have responded to various threads over the past year or so regarding the decision to acquire a 7.1 channel systems. Obviously, every audio and HT buff has the right to assemble the system that pleases them, and I do not mean in any way to disparage your intent. However, you might find a discussion from Bryston's newsletter about 6.1 and 7.1 channel systems informative. Go to the following links for some useful commentary about 6.1 and 7.1 channel HT:
1. http://www.bryston.ca/newsletters/55_files/vol5is5.html
(article titled "Encode vs. Decode Dilemma")
2. http://www.bryston.ca/newsletters/64_files/vol6is4.html
(main article: "The Great Capitulation")