lalibrairie: The Oxford Union Library, Oxford, United Kingdom On the walls are Pre-Raphaelites murals, painted by Dante Gabriel Rossetti, William Morris and Edward Burne-Jones. It also has a unique clerestory (Wikipedia will tell you all about it here).
"American entrepreneur Jay Walker& private library & so important (and massive) that his house was designed and built around it." From Flavorwire's 20 Beautiful Private and Personal Libraries. I want to build my house around my library!