Back in the day, sa tambayan (UPZS - Owl’s Nest) kami umiinom 
Ngayon ata Sarah’s at PCED (now UH or University Hotel) na lang meron sa Diliman. Milk tea na kasi uso inumin ng mga kids 
I heard Pop Up in Katipunan is a popular spot as well.
Meron nga rin palang thread about drinking spots over at #food-travel – After-hours drinking spots, you can check it out as well. 