This is absurd. If these electronic devices had the real ability to bring down a plane, they would simply not be allowed on board. If a mobile phone can bring down a 737, then the 737 should never have been deemed safe for flight?
I do put my Blackberry into "wireless off" right before takeoff, to save battery only. Ipod and laptop stay on at all times.
Also, funny I can use my Blackberry taxiing in but not taxiing out; the "danger" must be different.