The question is who would you choose to be? given that:
- you can only choose one time, one figure, then the device is broken for good, so pick carefully;
- once "teleported", you lose your previous memory, you'll become the hero/heroine and will live his/her life exactly as described in the book, including personality, love, pain, death;
- once the character dies, you're teleported back in the present and you will gain both your old memory and the fresh memory of everything that happened in this process. Your body and mind are restored like everything happened in just a second of sleep.
I have made up this context to differentiate the thread from "who's your favorite book character", I'm more interested in "whose life you'd want to live, first hand, no personal contribution, no risks attached".