Something
not mentioned about page numbers (AFAIK): it gives you an extra way to put a value on a book, like "Wow! This is great, but it's only 200 pages, so I should cherish each and every page (
word even)!".
Next to that it gives you a way to plan your bookreading; sometimes it happens that you know beforehand that you won't have much time to do serious reading in the next few weeks; you shouldn't start in a 1000+ page story, it would decrease the value you get from reading it, because it will be so very fragmented. It's perfectly OK however, to read a 200 page story in the same time because you'll easily finish it
...you could compare it to eating in a restaurant: if you've got time (and money) go eat in a fancy restaurant and order a 7-course meal. And go for a single course fish&chips if you haven't got time. Both meals are perfectly enjoyable and for both meals you should know beforehand how much time (=pages) you've got to choose the right one...
So for me, I would really like to have page numbers, including total page count. On screen. Not in the clumsy menus...