I am definetely going to buy an eReader sooner or later. I am actually interested in hearing your opinion on which one between K and N would be a better choice to hack. I like Nook better for the hardware seems more versatile and rooting is very very easy (the entire OS is on a microSD card inside the device). Yet, I think K's out of the box configuration is way better given the longer battery life and the ability to access free internet (at least a tiny part of it) from anywhere in the world.
What is your take?