Misconception about Component video
Assuming that his AVR upconverts video to the HDMI output port, there is no reason not to connect everything to the inputs of the AVR, only with a minor change. The most efficient way would have to be to connect the PS3 and OPPO DVD player via HDMI and connect the cable box and XBOX 360 via component. This would allow for HD audio via the PS3 and upconverted picture via the OPPO. Granted the XBOX 360 can output at 1080p via HDMI, but unless you are using a 60" TV or sitting really close, you will never see the difference between 720p and 1080p. So make it easy and don't require a switching of video on your display!