hi, unfortunately, I wasn't able to hold to my promise of only ereading: after some good 2 hours of reading alone (finished "Murders of Rue Morgue"), I took a break on some web browsing elsewhere and my daughter played Angry Birds for awhile. It's currently at about 20% right now, 4 hours straight of varied usage, mostly reading.
I'll turn now just to ereading again to find out how much more it can endure with such low charge...
*edit*
I was able to get one more hour out of those 20%. If I can get pretty decent 5 hours worth of usage on various activities, sure I can get at least 7 hours out of plain ereading...