You can certainly use the 7.1 outs for everything, but with my BDP83SE I've always prefered using the 2 channel outs as these are supported by stacked DACs. I also use a Grant Fidelity tube buffer between the 2 channel outs and the 990 CD in. This certainly isn't necessary but I like the effect.
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HT:
990/770
Oppo BD83SE
Pioneer Elite DV-47A
Magnavox HDMR513h DVR/DVD-R
Sony DVD megachangers-2
Sony CD megachangers-2
Monster power centers-2
Sony 48" rear projection SDTV
Roku video player
JVC AL-A158 Turntable
Polk RT-2000s,CS-650,XS-650s,RT80s
LFM-1EX
Hsu VTF-1
12" Velodyne

Family room:
OPPO 970
Sony 32" direct view HDTV
Denon 3801
Rolk RMs