if the cable box has only Component Video out, the easiest way to hook everything up would be to hook up both audio and video direct to the Yamaha 750 (it has component switching). It will require an extra cable for the video connection from the receiver to the tv, but it will facilitate component switching.
Now if the cable box and tv both have DVI or HDMI output/inputs, that's likely how you're going to want to hook it up. It may be worth experimenting though to see what gives you the better picture quality between digital (DVI and HDMI) or analog (component).
