Score one for eBooks as a learning tool. Jason Boog over at the GalleyCat blog made mention of what I consider to be a major advantage for students in cutting edge fields like Medicine. Instantly updated learning material.
When the publisher Little Brown issued an eBook only update about the H1N1 virus to their title "The Vaccine Book: Making the Right Decision for Your Child" they explicitly showed that the publishers now have a way to combat the lag times of traditional publishing, they don't even have to abandon print editions.
By simply giving purchasers access to a continuously updated electronic edition a publisher can ensure a textbook buyer that they will have completely up to date and relevant information about their subject despite any advances that may occur. They could package the text like software giving you the base text and two years worth of updates with the first purchase. After the term the student/teacher/professional could opt for further updates for an aditional licence fee, keep the product as is, or buy the next edition.
This could also help reduce the number of new editions that publishers need to produce allowing them to move towards something more resonable like a 5 year publishing cycle for textbooks. The publisher is rewarded financially for keeping their text up to date, professionals no longer have to cross reference between texts and monthly journals, and students could be less crippled by debt.
Obviously this is less of a concern for some fields (I am constantly aggravated by the parade of new Calculus editions being produced despite the fundamentals remaining unchanged for centuries... but I digress), but for fast changing sciences like Medicine this is a huge development. Now we just have to see how it will be used.