i find activesync to be the culprit with poor battery life. it will start every time the phone sync's its time with the network (ever time you change towers, ect.) so If you don't change timezones, you can completely disable the time sync in phone settings, otherwise I recommend what's in the following posts. (I think ludester was who turned me on to this, but I know others have posted this as well, but I can't find them with search)
http://forum.ppcgeeks.com/showthread...ime#post221719
http://forum.ppcgeeks.com/showthread...ime#post316075