Very good battery life with the iPhone 4:

[Irish Rose]

The iPhone 4 has the best battery life of any smartphone that I have had so far. I'm getting 7 hours of usage in a little under a 2 day period:

3G ON
WiFi ON
Bluetooth OFF
Location Services ON
Push Mail OFF, Fetch hourly ON.
Auto-Brightness ON, and set at 75%
My usage: Voice calls, messaging, Safari, iPod player,
Navigation, Weather & News, YouTube, Camera/Video, and email.

 

[jrmrbcax]

Best I can get.

 

[Irish Rose]

Best I can get.

Your settings and how you use your iPhone are going to have a big impact on the amount of time that you get out of a charge, which is why I posted my settings and usage above.

 

[ThatsMeRight]

Standard usage (some radio streaming, watching some videos, internet over 3G, some games and some calling). Battery of i4 is a huge improvement over the 3GS.