Thanks for all the responses!
I have not had much time to investigate lately. The problem seemed to go away when I moved the receiver away from the other components but after a couple days it was back (but fainter than before) and today after work it was back in full force. It was as loud as ever today while watching tv. The room is in the basement/lower level of our new house. The oil furnace is through a wall relatively close to the setup. I don't think it happens every time the furnace runs but am not positive (it provides out hot water so it runs year round). I have mostly high quality cables with the exception of the sat to rec cable which is a fairly high gauge no-name rca bundle (L,R,vid):
rec to speakers: monster wire w/ monst connectors
rec to TV: component
dvd to rec: component, dig coax
sat to rec: rca bundle (red, white, yellow)
Could this cable cause a prob? I have yet to hear it while watching a dvd but the wife says she has seen the problem during dvd operations. [We never turn the sat box off] Disconnecting this cable did not stop the buzzing noise.
Today when I was hearing the buzz again, I moved the speaker cable to the RH front channel and the noise stopped (coincidence or not, I do not know).
Also, I have the tv power cable plugged into the rec and the rest of the power cord run to an APC surge protector.
**I JUST REMEMBERED: I had to get one of those stupid Radio Shack remote wireless phone systems for the sat box which requires a phone jack. The sender/source is upstairs and the receiver is right next to the HT. What does it use? RF, I think. Maybe that is the problem?? I need to unplug it the next time we get the buzz in the HT.