Are you using one of those varaible-speed resistors with the ceiling fan? Those are notorious for adding lots of noise to the electrical circuit. You should try plugging your HT gear into a separate circuit from the one the ceiling fan is running on. Another thing that might or might not help is one of the surge-protectors/power-centers that have filters to reduce line noise, such as the Panamax line, though depending on how bad it is these devices may or may not solve the problem.