The Washington Post has an article in their Health section here that describes that describes new research showing that readers live longer than non-readers. I was glad to see it, although I don't think adding a few years to the end of your life is the most important reason for reading.
The best reason for reading is that it enriches your life. And it certainly enriches your children’s lives. Kids who are avid readers read better, write better, concentrate better, and do better in all of their subjects, across the board. I taught high school English for almost forty years, and found that it didn’t even matter much what my students read, as long as they had a love and habit of reading. Many of my best readers, as kids, read comic books, fantasy and romance and mystery series, and much popular fiction. A love of reading is the best educational gift you can give to your children.