As Ted said: nothing compares to the feel and smell of a real book. Also, the reader becomes a part of the action by turning the pages. If I had to choose, I'd choose a real book any day: something I can leave as a legacy, something I can lend or give as a gift.
However... with my situation as it is, living overseas, having real books is impractical. I cannot possibly bring all of the books I could read in a year with me. So, a Kindle fits the bill perfectly. And with a Kindle, as long as I dispose of the battery properly, I don't have to worry about impacting the environment as much. No cutting trees down to make an ebook.