yeah... down to 67% in 24 hours in offline mode... that shouldn't be.

At first I thought the N900 used basically no power in offline mode, but taking a closer look, it seems that it does...

For me from 97% full at 05:18 to 84%full at 11:58 in offline mode (while I'm asleep) it uses 13% in less than 7 hours.
I've since 11:58 been connected to wifi and skype/gtalk/msn (cellular off) and am down to 81% full at 13:39.

It seems to me that there is definitely an issue with constant slow draining of the battery, unrelated to being connected or not, and then of course usage adds to the draining...

The standby battery in offline mode should be much better than it is

***EDIT*** my battery life is still acceptable. I'm still trying to pinpoint the cause of a drain bug that seldom gets triggered, and drains my battery within 10 hours or so. But most of the time I get decent usage. about 15-18 hours always connected, listening to 5-6 hours of music, 30-45 minutes of phone calls, some internet/messaging(maybe 1-2 hours) and all of this usually while connected to wifi internet, and sometimes to 2G..
2G phone is almost always on except when I'm in areas with very poor reception, I just switch the cellular radio off and only use wifi.