If the receiver has high enough bandwidth to pass an HD signal, it shouldn't make much difference. The only advantage of running everything through the receiver is that it eliminates the need to change inputs on the TV for different devices.
On my system, I run DVI from the cable box directly to the display and toslink from the cable box to the receiver. That way I can use the TV's speakers for mundane TV watching without powering up the receiver. Component from the DVD to the receiver and S-video from the VCR to receiver and one component out to the display for those sources.
Mort
