I know many science textbooks also offer a CD-ROM version of the book. In the school where I am student teaching there are not enough textbooks for all of the students. Although the teacher has run off copies of the necessary pages, being able to present the students with pictures and films from the computer would be helpful. I delight in using CD-ROM's in my physics classroom. I, however, have learned to allow some variety of choice to fit the student's learning style and the level at which the student finds herself in the topic.
Students really benefit from the added visualization.