There was no noise or buzz with my Onkyo 886, no noise in another system set up wth my Klipsch Kg4 speakers with a DirecTv DVR, so I am sure the sat system is grounded. I have visually looked at it and it seems fine.
I got a Hum X and connected the Plasma to it. With the HDMI cable connected at the 7005 to the TV, and multiple HDMI cables connected to the 7005 except the DVR, no noise!
Connect the DVR via HDMI and the noise returns.
Connect the DVR via component video cables and the buzz is still there.
Tomorrow I am going to swap DVR. The one in th eroom now has a 3 prong plug, but I have a H22-100 (I think) in another room that is only a 2 pronger.