If you are using Google services(contacts, calender, email) with your pre, or any other imap idle service, you might, like me, be enjoying 20hr battery life tops.

I know I could turn off Facebook, Aim, and bunch of other stuff per the guide on this forum, but lets be frank that stuff is cool and you want it on, its part of the Pre goodness. So I may have a better solution :

nuevasync.blogspot.com/2009/07/push-e-mail-is-here.html

Nuevasync now does full exchange to all Google services email(this can be any email setup that supports idle, not necessary gmail), cal, and contacts(can also be plaxio) for 25$ a year. It's no secret that while IMAP IDLE is nice, its not the best for your battery, better then polling(which I found out is how the Pre does Google contact and calender sync, yikes.), but nowhere as nice as BES or Exchange Activesync. So why not activesync push all three?

Just thought I would share: If your battery is just not doing it through the day, this might be worth a try.

Hopefully this helps.