One of the most underrated spots in the CBD to watch the sun set! Located just off Reddacliff Place, the Brisbane Square Library offers great views of the city and the Brisbane River, looking over South Bank and the Cultural Centre precinct. Head up to the third floor right in the late evening for a beautiful view of the sky as night falls - the range of colours is dazzling and is perfect for photos no matter what the weather is like (it's the perfect place to watch a thunderstorm roll in over the city.)
Friday nights are even more atmospheric, with live music every week from 5:30pm - it's a great place to unwind after the work week and it's completely free to attend. You can catch a range of different local artists playing great acoustic tunes and enjoy the performance with a magazine, a (BYO) coffee, or just unwind (and it makes for a great relaxed study environment if you're still hitting the books on a Friday night, too). Live in the library is absolutely a hidden gem when it comes to low-cost entertainment and Brisbane's blossoming musical talents!
Hint: pick up a current program while you're there and find out about all kinds of upcoming cultural events and workshops - free movies and cooking or gardening workshops are a staple, all free or low-cost, and all Brisbane libraries offer programs and events for kids of all ages, especially over the school holidays.