Therefore, my rule is this: I only use the Nook to read things which are public domain. There's more than enough public domain stuff I want to read out there to keep me occupied. But if I'm going to pay for something, it's gonna be a proper printed physical book which I can keep for the rest of my life.
In some circumstances, you can even go a step further now. I stopped buying music about a year ago when I got a Spotify account and now 80-90% of my listening is through that.
I realized that most of my listening is to new/ephemeral stuff rather than stuff I want to listen to for years in which case, I'll just buy those albums if/when Spotify takes a dive.
In the future, I think I'll be reading books on my kindle, and then I'll consider whether the book merits a meatspace presence in my life. If so, I'll pick up a copy.
In the end, I'll likely have fewer books on my shelves, but what I do have will be a more meaningful representation of my tastes and values.
But I'm sure people felt the same about vinyl records. And now, if I want to check out a friend's music taste, I just look at their iTunes. I'm not old enough to know whether it's quite the same, but I'm not sentimental enough to think we haven't made massive improvements.
I suspect DVDs will be the next to go. (I don't have a DVD player of my own, but I like to have my fairly small collection where people can see it.)