Just thought I'd post one (likely last) update on the whole kindle / battery thing. Been using it in 'sleep' mode, just charged it for the second time today. And that first one was when it came out of the box. It's been over a month! I'm very impressed. Though, I did cut my reading short last night when I got the battery message.
1+ month, pretty damn nice. Full charge in 2.5 hrs. Very nice. If only we could see phone battery like that