One of the most beautiful libraries from within I have been in is the one in downtown Reno, NV which has an inside arboretum with a running brook, many trees, and other greenery.
http://libwww.washoecounty.us/mod.ph...04&page_id=160
Really liked the downtown Sarasota FL library which has a large aquarium in it.
http://suncat.co.sarasota.fl.us/Libraries/Aquarium.aspx