lccalvert,
you might have more luck sticking with 5.1 for now. You can use the extra moula you save from not purchasing the extra pair of QS4s and get a VP150 (instead of a VP100) and a pair of QS8s instead of the 4s. I suggest 5.1 only because there is very little 7.1 material available on DVD. It'll also make it easier on the pocket book and help to avoid the dreaded 'upgraditis'.

good luck

"Chickens don't clap."