The other Ian . I agree entirely. Many Receivers do not have sufficent bandwidth and are limited to s-vhs or composite switching. Given the choice you are better off bypassing the receiver altogether going directly into your display device if you have sufficent inputs.
One other point - when setting up an A/V processor of any degree of complexity it is really useful to be able to use a video output to see the OSD (On Screen Display).
The better processors will not degrade the video signal in any significant way and the best will use a pixel switch to allow you to have the picture and OSD present at the same time. The Arcam DAVE system does this, as of course does the new Arcam AV8. I personally don't know of any others, though no doubt the readership will enlighten me on this point