I'm getting about 6.5 hours of usage, which mostly consists of web browsing over WiFi. I have 3G on, brightness set to around 60% with auto-brightness on, bluetooth off, push off, notifications off. That lasts me the entire day, even if I use it heavily (by my standards), but it's not as good as what Apple advertises. I did restore from a 2G backup, but I'm unwilling to completely wipe the phone to start fresh. I don't want to lose all my text messages and stuff, and I shouldn't have to. I may try to "reset all settings" tonight.