Comparing the Price of an E-book to the Price of a Cup of Coffee?

I've seen people compare the price of an e-book to the price of a cup of coffee more than once in the past, and I recently saw it pop up again in a few places. It would be an interesting concept...that is if you like comparing apples with those proverbial oranges.

Now I'll be the first to admit that some e-book prices are over the top and I have passed on more than a few e-books I've wanted to read because I thought they were too expensive. I've posted about this several times. I have, I thin...