man im not really a heavy user, actually very light user.
ok my device usage as follows:
1) I turn on 3g all the time
2) For normal day, i normally leave my phone inside a locker for 8 hours. fully charged battery 90%, by the time when i finish work, left back 20% only. idle time 8 hours it eats up 70% of my battery?????
3) very normal usage, minimal game, mostly web surfing and facebook only. no tweeter or whatsoever..
4) Apps sync turned off all these while
5) fully stock, no root
6) no background launcher or whatsoever, simple wallpaper (non-animated)
definitely not normal .
check your apps.
install betterbatterystat like others mentioned.