looking at the onkyo HTIB..which best for 90% of viewing will be through hd-dvr directv receiver...plan on getting blu ray player sometime this spring...which of the onkyo htib would be best for me? 3100,4100,5100,6100?...also if i got one of the 7.1 setups, i would reduce it to 5.1 due to my layout...would i see much difference in sound quality between the systems because most of the viewing would be hd-dvr directv? thanks