I think this is such a complicated topic.
First, there are many books that I won't purchase because I think that what we house, we often become. For example, no Disney books because I think they are sexist, racist and classist. I will purchase great books for my kids any day of the week. When there is so much great literature out there, I certainly will not spend my jack on twaddle.
Second, while I want these books nowhere near my house, I recognize their educational value. To get one or two at the library is no big deal because they are a great jumping off point for grander discussions. Little Mermaid: She is only 16 and left her family to chase a man she never met; Our babysitter is 16--what do you think of that? He loves her even though the only thing he knows about her is that she is pretty and can sing well. Is that enough to marry someone? What else might he want to find out? And on and on.
Third, there are some books that I simply say, "I have read that X number of times, you know mommy thinks that book is boring. I will read it again in a few days. What can you find to interest both of us?" There is a book called Finders Keepers about two dogs and a bone that I hate. I think it is the only one that I limit. Now, of course, he taunts me, "I have Finders Keepers." So I have to reply, "You found it...you keep it!"
Fourth, I really do regret my early reading choices. I have so little time to read for pleasure now, I feel that I pist away a lot of free time with crap books. When I did read good lit, it was for book reports, so I tried to blow through them quickly and did not take all of it in. Like I said before, there is so much out there that is amazing, I just cannot see reading fluff for myself again. Maybe in my 80s when things slow down....