Hmm... the library at the Japanese Foundation of Kuala Lumpur which is just across the bridge from Mid Valley. I went there to study for JLPT or hang out with a friend and sit there reading manga/light novels on kindle all afternoon.

It's extremely quiet and the natural sunlight from the seats at the window is pleasing. They don't charge for entry but you have to register to be a member if you want to borrow books.

Link

Hope this helps V