Power and battery2
Built-in rechargeable lithium-ion battery
Charging via USB to computer system or power adapter
Up to 7 hours on 3G
Up to 14 hours on 2G
Standby time: Up to 300 hours
Up to 6 hours on 3G
Up to 10 hours on Wi-Fi
Video playback: Up to 10 hours
Audio playback: Up to 40 hours
I recently turned my 3G off after the guy at my local MacMan store advised me to do so. (no 3G here). Before that the best battery life I noticed was 8 hours usage with over 23 hours of standby, with just 2% left. I have push every hour with 75-80% brightness on. No Bluetooth.
Typically I am getting 6.5-7 hours usage with 15ish% left.
Amazing battery life in my opinion. Much better than my 3GS..