I'm curious to know if leaving any push notifications on (like AIM and APP News, or even email) affects the battery life at all. I'm thinking that since it's something running in the background, it must to some degree. I know that Apple claims that battery life has been improved with the 3GS, but I'm not seeing it. Could be because I'm now fixated on the % number instead of the bar, but the update to 3.0 seems to have shortened the battery life a bit ... could it be push being on?