I read if you are using stock messaging program theres an issue with it draining battery. Install something like handcent an disable stock messaging and restart phone battery life should get better.
I very rarely send or receive texts so I don't think this is my issue (but I do have Handcent installed).
My phone has been unplugged for 5 hours and my battery is now at 39% and droppping. I am so tired of having to charge 2-3 times a day. The only app that I really use is ebuddy messenger but none of the other apps are out of the ordinary.
This was a problem with 1.5 but has gotten much worse since going to the official 2.1.