Is there any advantage to running my HDMI cables through my receiver instead of directly to my tv?I've tried it both ways and I can see no difference.That's one less cable to fool with.

well you would be running the audio to the reciever via the HDMI. I take it that you are using either digital coax or toslink for audio then? As long as you dont want to do video switching with the reciever and have the OSD if it has one then there really is no advantage. a digital coax is much cheaper than a HDMI.

I'm running toslink from both the directv receiver and my Oppo dvd player to my receiver.

One reason receivers have this type of switching is to accomodate people that have multiple pieces of equipment that have HDMI hookups. This allows the user to only be required to run one cable to their projector or tv.