I used a video sender on my main TV for about a year (I didn't want the living room cluttered, so put the Tivo in a corner of the office). I found it to be fairly tempremental and I'd often get days where it just didn't want to provide a clear signal.

The wireless network played well with the video sender. I had an Apple Airport just a foot away from the transmitter which caused no problems, even when it was in heavy use. But if the laptop was used in the living room, it interfered. So it seems that the receiver is the most prone to interference.

An active bluetooth connection anywhere in the vicinity causes lots of interference (bluetooth devices in sleep are fine though). UK DECT phones are 1900Mhz, so they don't cause a problem. Microwaves completely destroy the signal, as do people walking between the transmitter and receiver.

My sender had 4 channels and it made little difference which one I picked. I think my airport was set to channel 10 or 13 at the time.