we all know of lag on an lcd screen, but what about on a receiver? if we run hdmi through a receiver (denon) will we experience lag because of the extra connected device?

It's possible, but I doubt it. Some receivers just due passsthrough with HDMI, others convert/upconvert/etc. the signal and in those cases it depends on the recivers components. It appears to me (recently bought a receiver) that most receivers with HDMI are better built.