Apple iPhone 4S

If you have an Android with 2.2 and up task killers really don't do any good. You just have to be careful about what apps you download because some will drain your battery pretty quickly. I have a G2 and the battery life is pretty good. I rarely play games on my phone, when I'm at work I turn off my auto-sync, adjust screen timeout, brightness, turn off touch tone sound (I can't stand that noise)...all those little changes save on battery life. I work 10 hour shifts and listen to my music all night on my phone w/o my battery dying.