Supposedly the newest 4G phones get mondo battery life. If I were due for a new phone I'd be looking very, very hard at a LG Revolution or Samsung Charge. Even so, they claim some 6-7 hours usage time, which even if you finished a ride by then, it would stink to be scrambling to plug in your phone. And it's possible that they only get that kind of life when they're actually receiving 4G signal, which in most places people ride bicycles, you wouldn't be.

My HTC Incredible (first generation) gets just about exactly five hours running iMapMyRide with NO accessories - that's with keeping it on the car charger on the way to the ride, no HRM, no cadence, no power meter, and with the display OFF, just recording the ride to download later (and for the live tracking which I haven't yet been able to get to work). I can easily get 13-14 hours out of either my Garmin 705 or 310XT.