In line with earlier thoughts about univeral DC power, let me ask why cell phones haven't standardized on USB (or a mini-USB plug) as an interface?
USB provides power. Not as much as some chargers, but enough to get a decent rate to many phones. And it has data, which can be used for phone control and configuration, speakerphone and headset interfaces, address book sync, ringtone download, memory card download, data-modem connections to PCs and anything else, all with one standard plug.
Every cell store has a rack of scores of adapters, chargers and cables. Each time you get a new phone they want to sell you new accessories, I guess. We have a standard. Why don't we use it, or extend it enough to be used.
(I'll admit it's not a good headset interface due to USB's silly master-slave protocol, since to connect to the PC the phone would be a slave, and to connect to the headset it would be the master. But this can be worked around, and I'll tolerate an extra headset jack.)
See below for some interesting safety ideas...
A standard port for phones would mean standardized docks for the home and for the car. In fact, cars would start building them in as a feature, feeding audio through the stereo for speakerphone and putting a mic on the sun-visor built in or talking to a wireless mic.
Homes would have standard docks which would connect to the 2nd line of the house phones, making the cell phone usable from the ordinary landlines, if you even have a main landline. (Some cell companies are offering a dock like this now.)
The car dock could also be connected to car functions, like turning or the brakes, so if the call goes silent during a traffic event, a tone could tell the other user to hold on. And presence settings could be triggered, so the phone could be made available for calls while stopped or while on the highway but not in city traffic, stop and go and other problem areas. This is all stuff that only really happens when the car's own computer is integrated with the dock. (Though in theory the phone could also tell these things by the way signals change, since phones are getting location awareness via GPS or the network.)
The phone could also make an emergency call upon trigger of the airbags, as some built-in systems do now. Again, all only easy to do with a standardized dock, though one could imagine a cell phone vendor putting an accelerometer in the phone and selling it as a live-saving device.