maybe the battery problem is also caused by default settings of N900 - e.g. mine had automatic connection to wifi enabled. So the first night I had it home, it automatically connected to one of the configured wifi networks - and probably because of that until morning, more than half of the battery was depleted (or maybe because it was after the first/second rechargement?)...

And there are, in my opinion, more similar flaws - like the vibrator acting each time one touches screen - which could too decrease the battery life...

Now that I have my n900 configured a little, the battery indicator stayed unmoved for 10 hours of not using the device - and after a whole day of light usage (mp3 playing, for a few hours, reading sms, playing supertux for 20 mins, a few minutes of wifi), 2/3 of the battery is charged... Therefore I find the battery life about the same, maybe even better, as e.g. HTC Wizard I used previously..

As krk969 wrote - it is not breathtaking, but noone can seriously expect such powerful device to last a week on battery (only if in offline mode and left untouched).