Livin on the Edge - NETWORK, THAT IS.

My evidence is only based on my own eyeballs, but I have many days of data now: Shutting off my iPhone's 3G access, using the legacy Edge data network instead, consistently reduces its idle-state battery drain by a lot. I'd say well over fifty percent.

I'm instituting a new personal policy of leaving it on Edge, except for those rare times when I'm not near a friendly WiFi point and need a high-speed internet connection. I recommend this practice to all my fellow iPhonophiles.

This is a minor bummer since the control to toggle Edge/3G is buried deep in the iPhone software control panel, requiring several taps and slides each time. But I choose that annoyance over the greater one of the phone begging for more juice well before my own bedtime, every day. With this new method, an overnight charge every other night keeps it full and happy.