A good friend and colleague of mine, Christophe Kirsch (lucidmonkey.com), who now resides in Canada sent me this link a couple of months back. It's the private library of Jay Walker and I'll let the article and link tell the story.
There may be greater private libraries out there, but I haven't seen one like this before.
"Nothing quite prepares you for the culture shock of Jay Walker's library. You exit the austere parlor of his New England home and pass through a hallway into the bibliographic equivalent of a Disney ride. Stuffed with landmark tomes and eye-grabbing historical objects—on the walls, on tables, standing on the floor—the room occupies about 3,600 square feet on three mazelike levels. Is that a Sputnik? (Yes.) Hey, those books appear to be bound in rubies. (They are.) That edition of Chaucer ... is it a Kelmscott? (Natch.) Gee, that chandelier looks like the one in the James Bond flick Die Another Day. (Because it is.) No matter where you turn in this ziggurat, another treasure beckons you ..."