In the U.S. print sales have been declining and at least part of that has to do with the electronic sales. Publishers need to take note as over half the market seems to be buying eBooks. Any new releases should be released in both formats as ignoring one or the other will likely result in reduced sales. Add to this news that libraries across the nation are starting to loan eBooks. At this rate of growth, I can foresee only select books getting print runs in about 5 years.
Like it or not, an eBook reader will be required in order to read new releases in the near future. Like the cell phone, it will be a once luxury item turned neccessity. So, bow down before your new eReader overlords.
Full disclosure: I have a Kindle and I love it. But only when my 10 year old isn't already loving it. I might have to buy a second one.