I have a suggestion for Apple. Yes, I know they are (not) listening.
I think the next iPhone/iPod touch should have a WiFi button. Like the power button on the top, maybe on the other side of the device, it should glow a light blue when it is on. You’d use it to turn WiFi on and off on the device, without having to dip into the settings all the time. It would then be incredibly easy to prolong your battery life.
What made me think of this? Running out of battery halfway through my flight yesterday, partially due to constantly looking for WiFi at the airports. (Partially due to watching a lot of TED, admittedly.)
There, Apple. All yours. The fifth button.