I am sorry to say I have never worked on the staff of any of these libraries:
http://www.curiousexpeditions.org/2007/09/a_librophiliacs_love_letter_1.html
Indeed the only one I have ever used as a reader, though I have visited as a tourist, is the old BM Reading Room.
They are all beautiful. My only quibble is that the list is so long, it would be very useful if it was possible to navigate around it more easily.

