moderate use: a tyipiical day in teh life of my n900:

unplug from charger at 8:00am
+- 30 of min skype calling,
+- 15 min of 3G calling
Wifi all day (only conected at home or office)
3G data not conected
+- 20 min MP3 audio
1 x sync

i get 7 hrs (some times less some times more)
wifi i think kills my battery as i talk more on weekends and am not connected to a wifi and my battery lasts 12+ hrs.