One: "I'm going to the library to buy a book."
The Espresso Machine -- and things like it -- will spell the end of bookstores. I don't have the numbers, but I have to think there are more public libraries out there than bookstores. And if there aren't right now, there will be. You won't go to a store to buy a printed book. You'll go to a neighborhood library.
Two: "What kindle are you reading?"
This is my nightmare, that the post-print generation does away with the term "book" and turns Amazon's Kindle trademark into the generic for electronic books.