You bring up many good points. My ideal library is definitely comprised of books I love and it would not contain books that I don't enjoy but "look good on the shelf". Having said that, I am not really considering collecting particular book editions for their monetary value/rarity either.
My question on print/binding quality was more about having books that will last a long time and are beautiful objects - the latter being one of the chief reasons why I can never really move on to eBooks completely. I have many books already on the shelf that I want to keep but I could consider trading them for a nicer hardcover edition. Scratches and stains do not really worry me, a well read book can certainly look like one, too.
Letting go of books is hard but I know that I can always get a new copy (perhaps a different edition though) if I prune too harshly and lose a copy that I find myself pining after later.