We flew to Texas for 10 days. I took one small suitcase--small enough to count as carryon--plus my computer... plus my kindle. Knowing Kindles are electronic and therefor can't be used around takeoff and landing, I took three real, paper-backed books (and read them). But all the rest of my reading supplies were on Kindle, and they really didn't take up very much space--hence one small case.
So, Pros and Cons of kindle vs paper, as deduced on a 10-day trip to Texas: