Thought I'd share my findings regarding battery life and 3G data connection.

I have had my N900 for about a month already. Did all kinds of battery tests/optimizations described on this forum and on other sites.
Battery optimization, i.e. adjusting display brightness, disconnecting from the internet when not using it, not having a lot of widgets running, does work, however, I have found that the biggest battery drainer turns out to be T-Mobile 3G data connection. It drains battery faster than a Wi-Fi connection (even at 100mW setting), so if you want your battery to last significantly longer, do not set your device to automatically connect to T-Mobile internet connection.

If your results indicate otherwise - please post a reply.

i second that i had the same problem till i disconected 3g only use it when i need it

I would have to agree. This thing sucks down the charge fast. I've been carrying a charger around with me all the time. I just turn the 3g off and use edge if I dont have wifi around. Edge is still quick for the most part.