Is switching 3G/4G off to save power a cheap trick?
If you still want to be downloading stuff, then probably yes, switching off 3G probably won't save you much power / battery life. However, when my battery is running low, switching off 3G can make the difference between the battery making it until I get to a charger or not. Obviously in those conditions I stop surfing or doing anything data-related as well, but even just for being in standby and receiving or making calls, 3G uses a lot more power than GPRS / EDGE / UMTS.