I bought my Kindle 3 just after they were released in Australia - Oct 2010 (I think). I had already bought the IPad just a few weeks previously. I have always been a bit of a bookworm but there would have been long stretches of time when I didn't read all that much. All this has changed since I got the Kindle and I have developed a voracious appetite for books - and Kindles. I now own three of my own, another that is on my account but given to my daughter. I have also bought one for my son and influenced another son to buy one for himself and then one for his wife. Amazon should really like me.
So, to answer the question, before the Kindle, an IPad for a few weeks but otherwise, paper books.