I just posted some of my thoughts on the battery issues I have been experiencing and a reader sent me a link to this T-Mobile forums discussion where it seems the way to improve the battery life is to turn everything off. It is funny that someone actually had to post the details about this because it is obvious that turning off the 3G, WiFi, Bluetooth, GPS, and auto-syncing will conserve your battery. However, didn't you just pay good money for a powerful mobile computer that lets you stay in touch and connected with the world at all times. If you bought the G1 to use primarily as a mobile phone, then I think there are some valid tips in this forum. However, why not just buy a rock solid Nokia phone that provides much better call quality if all you want is a mobile phone?
I actually rarely use GPS (it is inconvenient to dive through the menus to toggle the receiver) or WiFi and already have my brightness at less than 50% (it is plenty bright even at this setting). I need to add an AnyCut toggle for 3G though since the T-Mobile 3G network is still quite limited and only works for me at the office so I could save battery life here. I won't turn off the AutoSync feature because that is the main reason for having a Google phone, but I will turn off the Contacts portion since I rarely change my contacts and that is something that needs autosyncing.
Do you have any other battery tips, other than returning the device for a power efficient device like my awesome Palm Treo Pro?