Of course YANBU! :o
I am lucky to work with books all day as I work in a library. I would love to qualify as a librarian one day so that I can do all the hardcore stock work, I find it fascinating. NCIS - my county is actually doing a 'donation drive' at the moment, we are strict on quality/age though. We aren't closing any of our libraries so it was our stock budget that had to be cut. It's greatly appreciated when customers donate books to us (even though some don't get added to our stock - they get sold instead so still benefit the library) :)
I used to volunteer in a charity shop and agree it is really frustrating seeing books go unsold - it was devastating sorting through donations and chucking out readable books because they didn't make the grade. They do get recycled for money though so they aren't going to waste.
I have a kindle too, not nearly as well stocked as some people's - I am trying not to clutter it up. I use it mainly for 99p daily deals and free classics as I refuse to pay full price for books - I would never go into waterstones, I just can't afford it, unless it was for a present or a uni book in which case I always look online first. If we had an independent bookseller here though I would use it when I could, as I do with a toy shop. Anyway, generally I use the kindle or the library for fiction, as I am very unlikely to read a book more than once. For non fiction though I much prefer real books. That 'thud' as I used to find the right Encyclopaedia Britannica with my dad when doing my homework, and set it down on the table. So happy :) I have to say those interactive textbooks you can get on iPad look pretty incredible though - just can't reasonably afford any.
My real weakness is children's books - as well as all the amazing modern books available I also have an obsession with finding the ones I loved as a child, including books my two aren't old enough for yet. They have an enviable collection of non fiction - usborne and dorling kindersly type stuff. I am stupidly excited about the day they start getting research type homework from school.