dgilley,

Just a couple of thoughts...Is all your HT gear on one circuit? Is it possible that the ground could be different for multiple circuits? If you have two or more I'd start looking at connections at switches and wall plates. Also, are there any motors (refrig or freezer), dimmers, timers, or other noise generators on the HT circuit(s)? I had an electrician friend tell me to be wary of aluminum wire since it will loosen in the connection over time. If all else fails it might be time to call an electrician to diagnose the problem.