I haven't read this whole thread, but wanted to chip in my experiences with my new N900 regarding battery.

In a nutshell, I am disappointed.
It's worse than my previous Nokia N95.

I have it full charged when I leave work. Then a 1:30 hour commute, using it a fair bit [what I bought it for] see's the battery down to about 25% charge if that.

I am finding I need to charge it 3 times a day just so it doesn't quit on me.

Maybe it will lesson when the excitement/novelty wears off. But I did buy it to use it for everything I am using it.

Does anyone know about a bigger, heavy duty battery for this?

Thanks