The Louise Riley branch of the Calgary Public Library is small and quaint, but packs a surprising amount of punch in its book selection. It is always bustling when I go in, but never packed. They have a small reading area with tables and chairs that is perfect for late night studying. This library is well lit, with a soft yellow glow that doesn't hurt your eyes staring at it. They have a great selection of kids books, a decent non-fiction section and feature book readings on a fairly regular basis.
Although it is fairly small, this location was renovated recently and is a great place to stop and grab some info. The handy hold system of the library means that even if they don't have that book, you can request a pick-up at any location. All in all, one of my favourite locations.