I have been a long-time Nook owner: I have a first-generation Nook which I got for my birthday back in 2009. I have always loved it and could not imagine switching to another brand.
But, I got a Kindle Paperwhite for Christmas and I'm so in love with it (the light weight! the backlight! the ease of use! the smart cover!) that I cannot imagine ever picking my Nook up again. I actually have two new releases that I pre-ordered months ago, waiting on my Nook to be read, and I can't put my Kindle down for long enough to read them. Even though they are books I really want to read!
Do you have an e-reader? Which one do you have? Do you love it or hate it, and why?