T-Mobile G1 battery life solution; turn off everything!
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?