When the kids were younger, they loved hearing the same books over and over! Our son just turned five though, and he has a real hunger for new books and stories. He made the switch at some point between 3 and 4 years of age. Our daughter still likes to hear the same stories over and over though... she's 3 and can't get enough of the various Mo Willems books.
Do your kids like to read different books every day, or have the same books read to them every day? ETA: How old are your kids?