I would like to know just how much better is watching a movie in 7.1 versus 5.1? I mean, is it as big of a difference as 2 channel v/s 5.1 is? Does the difference in the 'wow factor' depend on the size of the room? I am planning to build an HT room in my basement (15*20*7) and am wondering if I should upgrade to 7.1 in the process and get wiring done for the 2 extra channels. Thanks in advance for your response.