A note on possible interference between wireless devices:

Just for fun I tried using my GPS on my road bike to generate a gradient profile of a ride. I found that the GPS interfered with my Cateye Wireless computer, causing it to read about 8 miles low for a 40 mile ride (the speed also fluctuated wildly even though I was riding at a steady pace). The GPS also interfered with my old early 1990's Polar heart rate monitor, causing it to read too high (frequently well above 200). I have used the GPS with my newer 2000 Polar heart rate monitor in the past and it doesn't seem to interfere with that.

I've never seen any interference with any of my wired cyclocomputers.