Scanning settings for rich content e-books

I want scan book prints and create a rich content (photo) e-book with the scanned images. What scanning settings would you recommend? 300dpi, 600dpi? I suggested true-to-size reproduction @300dpi. A collegue told me to scan at a higher resolution in order to make the images zoomable. Does anybody have any inputs on this?

Thanks for your help,

Philipp