I have studied here and is in love with it's architecture. My favorites are the Main Building, Beato Angelico Building (Archi-CFAD) and the Santissimo Rosario Church (esp the interiors). The Museum inside the Main Building, Quadricentennial Park, Arch of the Centuries and the Botanical Gardens are worth visiting. I love the "ancient feel" of the whole place and though I'm all for the improvement of the University (by erecting new buildings), I hope they maintain the amazing Spanish-era architecture. There's also the Publishing House, the souvenir shop inside the Museum, and stalls inside the AMV Carpark that sells UST jackets, key chains, etc. There are lots of food chains within and outside UST so you will definitely not starve (the ice cream stuffed inside buns that are being sold inside the University is a must-try!)
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.