My lasts at least one week (I can't say in page turns)...
=> I read news from different sites everyday (downloaded via calibre) => +100 pages/day; sometimes +200 page turns per day only for newsreading
=> also reading magazines, books, .... (50-100 pages a week? - never counted it
- but that includes reading PDF which is a lot heavier)
=> using it with calendar (incl. syncing) en tasks (Shuffle app)
=> checking my mail sometimes (sync. also)
=> a little surfing each week (and a general sync nearly every day)
I do kill apps regularly with Advanced Task Killer (or sth like that?)
So... I'm satisfied with the battery and usage time (+1 week for an Android device)