I have to chime in, too. I agree with Eddie...if you want to donate an old quilt top to a museum or something, then by all means leave it unquilted. Are you going to sell it? I doubt it, so the "value" issue of leaving it unquilted is kind of moot. If you are going to pass it down through your family as an heirloom, then it will have more "value" to your family as a finished quilt. It will not only make it easier to "maintain" the condition of the quilt, but it can be displayed in a much more pleasing way. Who wants to look at a ragged edged quilt top, unless it's framed behind glass with the edges tucked under?
It's totally up to you, but if they were mine, I would finish them the way the maker would undoubtedly have done, and then hang, drape or otherwise display and enjoy them.
I like to think the ladies who made the tops are up in Heaven looking down, thinking, "Ah, now my work is finished!" :thumbup: