Do you have email/services synching (what frequency?)
Are you on 3G most of the time or WiFI or neither?
I know I can almost double or more my battery by turning 3G data and wifi off
Well, it's not been used as much in the day, but it has either wifi or mobile data connection all the time. Data synch is on, with Gmail, UK weather, Newsrob, Seesmic (Facebook), Tweetcaster - all on hourly sync with Gmail being push of course.
So, with a period last night on Airplane mode with the alarm functionality being used, I was at 1day 12hours @1%.
Not bad and the best I've had for a long time.