Moll - you've no idea how often I lie awake at night thinking about exactly this issue! It's taken me 25 years (so far) of fairly intense collecting to amass what I think is a very fine collection of folk song/folkloristics/folklore books. I can't bear to think what will happen to the whole lot after I'm no longer around... Most places these days - university libraries, etc - don't have the capacity or resources to take them in. I'd probably have to arrange in advance to pass them on to a similarly minded person.