Hmm, I think if it was in the print book, it should be in the ebook. Anything extra from that is too much, IMHO. If a book has some illustrations, maps, etc, I _want_ those in the ebook.
That's another reason I like µbook so much. Most of my ebooks are in zipped html format, so I can pick and choose if I want to include those large images (I can even resize them and use the smaller image in many cases). The zipped file usually has a smaller footprint than the same ereader or mobipocket book, too.
Now if only µbook supported rar archives.... mmmm......