WE HAD TO SOURCE power adapters for several American visitors this summer in Ireland because their battery power was so abysmal. They weren't stupid so they didn't use the phone to call anyone but they were using their iPhones as entertainment devices, cameras and wifi browsers. They rarely got more than four hours' use out of their iPhones when playing music, shooting photos and browsing. And from my own experience, there is no way the 3G iPhone outlasts a Nokia E90 when used during the work day. I know my experience is only anecdotal because Strategy Analytics tells people the 3G iPhone holds up well, saying standby time on the phone is average for a 3G handset. Maybe so, but 3G iPhone standby time is not as good as Nokia E90 standby time when hanging out in my Bihn bag. In fact, my hands-on experience suggests the iPhone is the most energy-sapping mobile telephony device I have ever used.
I wonder if Apple actually understands how data usage can deep drain a small battery. It seems that every iPhone update heavier than 200 MB hails better power management, suggesting to me that there's a lot to be learned by software to make its operations more energy-aware.