If you can afford to buy the books (and can keep your house from becoming overrun... even as regular library users, we still accumulate tons of books), that is great. I will say that D had a hard time finding her own books at the library for a while. Sometimes I would go down the shelves with her, pull stuff out, and give her a quick summary. She would glance, say yes or no, and it would go in the bag or back on the shelf. She didn't read everything we brought home, but a lot of it. If I just left her alone with the bag in the kids section, I would come back later and find the bag empty. Then she discovered the teen section when she was about 11, and was able to find more stuff there. She rolls her eyes at teen angst (and vampire novels, except Dracula :)), so she just ignored that stuff. Now she does her own selecting.
One of the great pleasures of parenthood for me has been finding/sharing my favorite books with my kids. So sometimes I suggest something for her, too. I have learned not to take it personally when they don't like something I loved. I have also learned not to sweat it if they don't read all that they bring home. They can always check it out again later if they want it.
One other thing is that if you live in a metropolitan area, you could try some different branches of the library. Each one has their own "flavor" in my opinion. The librarians decide which books to purchase, and which of the older ones to keep. And how to display them. The library in the big suburb near our house has a lot of the "junk" materials you mentioned prominently displayed. But the smaller branch in the little town by the river that is an equal distance away has a much less flashy, and in my opinion more interesting collection of kids and teen fiction. Too bad if none of your local branches/systems have a good selection, though.
Regarding re-reading, I checked the same books out of the library again and again as a kid. We had those cards that you wrote your name on, and on some cards my name is the only one, again and again over the years. So you can re-read, and still save $ and storage space. Also, our library allows online searching and putting a book on hold. They e-mail us when the book is in, and we have 7 days to pick it up. Sometimes it is in our branch, and sometimes it is from another branch. Either way, they will get it to our library's hold shelf and hang onto it for a week. We can even search all over the state and request stuff our library system doesn't have (I use this sometimes for out of print things). There is pretty much always something waiting for us on the hold shelf, so even if we don't find the thing we want on the shelf, it is never a wasted trip. Again, too bad if your library doesn't have these capabilities.
It probably also helps that we have a library "habit". We go at least once a week (and frequently complain to each other that we wish they were open on Friday nights, as that would be the most convenient time for us!).
