Not to get into the rest of the debate, but I certainly have to disagree with this point, as others have. I’ve been through security at many airports in Europe, Asia, and Canada and for the most part they don’t seem much different than in the U.S.
I don’t know how we got onto Israeli security – that’s obviously a very special case.
This rule isn’t about whether your iPod turns on or off, or even the theoretical risk of interference with onboard equipment. This rules has to do with the simple fact that landings and takeoffs are the riskiest phases of flight, and if something is going to go wrong, it’s most likely to go wrong during these phases, and if it does go wrong, things are going to be happening very quickly and they want you to be able to hear the flight attendants rather than listening to music, see what is going on around you, and not get trapped in your seat because you’re tangled up in headphone wires or unable to close your laptop/stow the tray table fast enough, etc.
Also: keep your shoes on. Broken glass and metal, burning jet fuel, snow, ice, etc which may be encountered during an emergency evacuation suck even more when you’re barefoot!
As well as what mnemosyne said, it’s another object that’s likely to fly off and hit someone (you are the most likely target) if things get bumpy. There was an Iberia flight a couple years back which had a rough landing, with a result of some bruises and a couple of broken arms: the people who got hurt had all taken off their seatbelts already, some got hit by their own items.