I'm also experiencing incredible battery drain since the update to GB last week. It's at a point right now where I can't make it to lunch with little to no usage on my Thunderbolt. Without being next to a charger at all times by phone turns into an expensive paper weight in less than 5 hrs.
I called Verizon yesterday and they are sending me a new battery to see if that will help but I don't believe that's the problem because I never experienced battery drain like this on Froyo.
Here's an example of what I'm experiencing...
On battery for 4hrs 52mins
Unplugged phone from charger at 7am, sent emails for about 35mins while carpooling on the Good Enterprises app my company uses for corporate email, got to work and sat my phone on my desk... touched it may 3 or 4 times to respond to a few txt messages during the mornings. Got up from my desk at 11:50am to go on a lunch appointment and my phone was at 3% battery life remaining.
When I checked my battery usage it broke down like this..
Display 80%
Cell Standby 7%
Android System 5%
Andriod O/S 5%
Messaging 2%
Bluetooth 1% - Bluetooth is turned off so I'm not sure why it is using battery
Run phone on 4G network all day, I am not rooted, running stock GB OTA, use no WiFi when away from home, no GPS, no Bluetooth, manual sync, no animations, screen brightness at lowest possible for viewing, black background, screen timeout at 1min
Any help you have I would greatly appreciate it because I really like this phone but it is useless if I have to shut everything off, use 3g, and alway worry when I'm away from a charger for more than 3 hours.
Thank you
Nate