These days, I read a lot of books on an iPad 2 using the Kindle app. It is for the most part a very good experience, especially for recreational reading. As millions of others have noted, having an electronic device loaded up with a mini-library of e-books is especially valuable while traveling, which is when I do a lot of my reading.
The other day, on vacation with the family, I came across a pitfall. I was reading the old football novel North Dallas Forty (thanks to Henry for the suggestion, and all of you for other suggestions). It's pretty entertaining -- especially the race stuff and drug stuff. As it happened, my 9-year-old daughter was curled up beside me reading her book (The Doll People). She took at look at what I was reading. Her eyes immediately found a four-letter word.