I have experimented with different tips here and my battery has been really good. I have actually never had a smart phone battery last so long. I work from my home office. Yesterday I took my phone off the charger at 7:15AM. During work hours I do not use the phone very often. It mainly sets on my desk. I do check out the market a few times a day and tinker a little. At 7PM last night when I picked up the phone to really use it my battery was still at 82%. This is with the GPS on, Wifi on, bluetooth off, and no 4G here. Also I have an Airave which gives me 5 bars of signal. My previous phone was a Treo 800w and under the same conditions it would be at about 55% for the same time frame. I did the GSM phone change. I also have signed off of GTalk and have it set to not automatically sign me in. I use battery indicator to show battery % and I do not use a task killer. I use exchange for my email and I also have a gmail account using the gmail app. No friend feed and I have facebook to update every hour. Weather is updating every hour. News is set to manual update as is stocks. Sports Tap is installed and set to update every hour. My battery has been this good for the past two or three days. This mourning I pulled it off the charger at 7Am and didn't look at it again until 9:30 and the battery was down to 68%. I looked to see what might be different today and the only thing I could find was I had a notification for facebook that had been in the notification area since 6:30 this mourning. I went into the facebook widget setting and turned off notifications. I recharged the phone and pulled it off the charger at about 10:30AM. The first thing I noticed was that I didn't get the usual quick battery drop. Thirty minutes later it was still at 100%. The battery has even been better than before. Normally the indicator would drop 7 to 8% in the first couple of hours but would level out after that. Today it is 6PM and my battery is at 94%. Granted I have not done much with the phone but just pick it up and play with it a few times but losing on 6% in 7 hours in almost unbelievable. I think this proves (to me at least) that wifi and gps are very efficient and that you don't have to cripple the phone to get good battery life. For those who have had terrible battery life you might try and turn off notifications in the facebook widget. That also stopped my quick first 10% battery drain.